interp: fix cd builtin: call a system function to determine access instead of reverse-engineering it ourselves
#1107
| Job | Run time |
|---|---|
| 36s | |
| 1m 21s | |
| 1m 2s | |
| 2m 48s | |
| 2m 0s | |
| 1m 5s | |
| 7m 11s | |
| 5m 38s | |
| 21m 41s |