Android 12: df fix integer overflow in computation of Total row

[cre4ture]

I create this issue from a finding from pullrequest #5821.

When running tests of uutils df on my own android phone (not on AVD),
they are failing due to integer overflow:

---- test_df::test_default_block_size stdout ----
run: /data/data/com.termux/files/home/rust/coreutils/target/debug/coreutils df --output=size
thread 'test_df::test_default_block_size' panicked at tests/by-util/test_df.rs:485:10:
Command was expected to succeed. Exit code: 101.
stdout = 
 stderr = thread 'main' panicked at src/uu/df/src/table.rs:105:22:
attempt to add with overflow

The fix that I'm working on in PR #5821 can handle this and the result is:

~/rust/coreutils $ target/debug/coreutils df -Ti --total
Filesystem                             Type                   Inodes  IUsed                IFree IUse% Mounted on
/dev/block/dm-15                       erofs    18446744073709551615   3141 18446744073709548474    1% /
tmpfs                                  tmpfs                 1457181   1460              1455721    1% /dev
tmpfs                                  tmpfs                 1457181     65              1457116    1% /mnt
/dev/block/by-name/metadata            ext4                     4096     34                 4062    1% /metadata
/dev/block/dm-16                       erofs    18446744073709551615   3002 18446744073709548613    1% /system_ext
/dev/block/dm-17                       ext4                      304    298                    6   99% /product
overlay-overlay                        overlay  18446744073709551615      0 18446744073709551615    0% /product/app
overlay-overlay                        overlay  18446744073709551615      0 18446744073709551615    0% /product/priv-app
overlay-overlay                        overlay  18446744073709551615      0 18446744073709551615    0% /product/lib64
overlay-overlay                        overlay  18446744073709551615      0 18446744073709551615    0% /product/lib
overlay-overlay                        overlay  18446744073709551615      0 18446744073709551615    0% /product/overlay
overlay                                overlay  18446744073709551615      0 18446744073709551615    0% /product/etc/permissions
overlay                                overlay  18446744073709551615      0 18446744073709551615    0% /product/framework
/dev/block/dm-18                       erofs    18446744073709551615      0 18446744073709551615    0% /vendor
/dev/block/dm-19                       erofs    18446744073709551615      0 18446744073709551615    0% /odm
/dev/block/dm-20                       erofs    18446744073709551615      0 18446744073709551615    0% /my_product
/dev/block/dm-21                       erofs    18446744073709551615      0 18446744073709551615    0% /my_engineering
/dev/block/dm-23                       erofs    18446744073709551615      0 18446744073709551615    0% /my_carrier
/dev/block/dm-24                       erofs    18446744073709551615      0 18446744073709551615    0% /my_region
/dev/block/dm-25                       erofs    18446744073709551615      0 18446744073709551615    0% /my_heytap
/dev/block/dm-26                       erofs    18446744073709551615      0 18446744073709551615    0% /my_stock
/dev/block/dm-27                       erofs    18446744073709551615      0 18446744073709551615    0% /my_preload
/dev/block/dm-28                       erofs    18446744073709551615      0 18446744073709551615    0% /my_bigball
/dev/block/dm-29                       erofs    18446744073709551615      0 18446744073709551615    0% /my_manifest
tmpfs                                  tmpfs                 1457181     70              1457111    1% /apex
/dev/block/loop5                       ext4                       32     20                   12   63% /apex/com.android.apex.cts.shim@1
/dev/block/loop5                       ext4                       32     20                   12   63% /apex/com.android.apex.cts.shim
/dev/block/loop6                       ext4                       32     23                    9   72% /apex/com.android.appsearch@300000000
/dev/block/loop7                       ext4                       48     35                   13   73% /apex/com.android.i18n@1
/dev/block/loop6                       ext4                       32     23                    9   72% /apex/com.android.appsearch
/dev/block/loop7                       ext4                       48     35                   13   73% /apex/com.android.i18n
/dev/block/loop8                       ext4                       32     29                    3   91% /apex/com.android.wifi@319999900
/dev/block/loop8                       ext4                       32     29                    3   91% /apex/com.android.wifi
/dev/block/loop11                      ext4                      304    290                   14   96% /apex/com.android.vndk.v31@1
/dev/block/loop11                      ext4                      304    290                   14   96% /apex/com.android.vndk.v31
/dev/block/dm-31                       ext4                      112    112                    0  100% /apex/com.android.art@341311100
/dev/block/dm-31                       ext4                      112    112                    0  100% /apex/com.android.art
/dev/block/dm-32                       ext4                       32     28                    4   88% /apex/com.android.permission@341311000
/dev/block/dm-30                       ext4                       32     25                    7   79% /apex/com.android.extservices@341317010
/dev/block/dm-32                       ext4                       32     28                    4   88% /apex/com.android.permission
/dev/block/dm-30                       ext4                       32     25                    7   79% /apex/com.android.extservices
/dev/block/dm-33                       ext4                      176    167                    9   95% /apex/com.android.conscrypt@341310090
/dev/block/loop15                      ext4                       64     50                   14   79% /apex/com.android.runtime@1
/dev/block/dm-33                       ext4                      176    167                    9   95% /apex/com.android.conscrypt
/dev/block/loop16                      ext4                      608    596                   12   99% /apex/com.android.vndk.v30@1
/dev/block/loop15                      ext4                       64     50                   14   79% /apex/com.android.runtime
/dev/block/loop16                      ext4                      608    596                   12   99% /apex/com.android.vndk.v30
/dev/block/dm-34                       ext4                       32     20                   12   63% /apex/com.android.tzdata@314012010
/dev/block/dm-34                       ext4                       32     20                   12   63% /apex/com.android.tzdata
/dev/block/dm-37                       ext4                       64     58                    6   91% /apex/com.android.media@341312020
/dev/block/dm-37                       ext4                       64     58                    6   91% /apex/com.android.media
/dev/block/dm-36                       ext4                       32     20                   12   63% /apex/com.android.scheduling@340819220
/dev/block/dm-36                       ext4                       32     20                   12   63% /apex/com.android.scheduling
/dev/block/dm-35                       ext4                       32     31                    1   97% /apex/com.android.os.statsd@341410000
/dev/block/dm-35                       ext4                       32     31                    1   97% /apex/com.android.os.statsd
/dev/block/dm-38                       ext4                       32     27                    5   85% /apex/com.android.mediaprovider@341313030
/dev/block/dm-38                       ext4                       32     27                    5   85% /apex/com.android.mediaprovider
/dev/block/dm-39                       ext4                       48     36                   12   75% /apex/com.android.adbd@340912350
/dev/block/dm-39                       ext4                       48     36                   12   75% /apex/com.android.adbd
/dev/block/dm-40                       ext4                      128    114                   14   90% /apex/com.android.media.swcodec@341312020
/dev/block/dm-40                       ext4                      128    114                   14   90% /apex/com.android.media.swcodec
/dev/block/dm-41                       ext4                       16     16                    0  100% /apex/com.android.neuralnetworks@341010080
/dev/block/dm-41                       ext4                       16     16                    0  100% /apex/com.android.neuralnetworks
/dev/block/loop27                      ext4                       32     26                    6   82% /apex/com.google.mainline.primary.libs@331059000
/dev/block/dm-42                       ext4                       32     21                   11   66% /apex/com.android.cellbroadcast@341311010
/dev/block/dm-42                       ext4                       32     21                   11   66% /apex/com.android.cellbroadcast
/dev/block/dm-43                       ext4                       32     20                   12   63% /apex/com.android.ipsec@340914280
/dev/block/dm-43                       ext4                       32     20                   12   63% /apex/com.android.ipsec
/dev/block/dm-44                       ext4                       80     73                    7   92% /apex/com.android.tethering@341310230
/dev/block/dm-44                       ext4                       80     73                    7   92% /apex/com.android.tethering
/dev/block/dm-45                       ext4                       32     26                    6   82% /apex/com.google.mainline.primary.libs@341339070
/dev/block/dm-46                       ext4                       16     16                    0  100% /apex/com.android.resolv@341311030
/dev/block/dm-46                       ext4                       16     16                    0  100% /apex/com.android.resolv
/dev/block/dm-47                       ext4                       32     24                    8   75% /apex/com.android.sdkext@341110080
/dev/block/dm-47                       ext4                       32     24                    8   75% /apex/com.android.sdkext
/dev/block/bootdevice/by-name/cache    ext4                   114688     55               114633    1% /cache
/dev/block/bootdevice/by-name/userdata f2fs                 12812797 347711             12465086    3% /data
/dev/fuse                              fuse                 12812797 347711             12465086    3% /storage/emulated
/data/media                            sdcardfs             12812797 347711             12465086    3% /storage/emulated/0/Android/data
/data/media                            sdcardfs             12812797 347711             12465086    3% /storage/emulated/0/Android/obb
total                                  -        368934881474246778279 1402723 368934881474245375556    1% -
~/rust/coreutils $ 

One can see that some entries (of type erofs) report inodes number at exactly (or close to) 18446744073709551615 which is the maximum number a u64 can represent.
I also tested the GNU implementation for this (on a erofs on my ubuntu) and it turned out that GNU also is not handling it porperly. It does a silent integer (u64) overflow in this case.

Therefor my proposal is to use a u128 for the total sum of inodes. I know that this is slower than u64 as its probably not natively supported, but we are not accululating millions of numbers such that it should not be significant.

I will continue working on it and provide a seperate PR to #5821