survey: collect stats from blobs during treewalk #677

Job	Run time
config	7s
fuzz smoke test	39s
win+VS build	0s
sparse	2m 43s
linux32 (daald/ubuntu32:xenial)	1m 43s
linux-musl (alpine)	1m 38s
pedantic (fedora)	1m 45s
static-analysis	3m 33s
win+VS test	0s
win build	2m 33s
linux-asan-ubsan (ubuntu-latest)	2m 0s
documentation	1m 28s
linux-gcc (ubuntu-20.04)	1m 7s
linux-gcc-default (ubuntu-latest)	1m 10s
linux-leaks (ubuntu-latest)	44s
linux-reftable (ubuntu-latest)	1m 19s
linux-reftable-leaks (ubuntu-latest)	48s
linux-sha256 (ubuntu-latest)	1m 15s
linux-TEST-vars (ubuntu-20.04)	1m 8s
osx-clang (macos-13)	51s
osx-gcc (macos-13)	1m 28s
osx-reftable (macos-13)	45s
win test	0s
	28m 44s

Provide feedback