fix(wasi): cp attribute preservation and reflink handling

[eduardomourar]

cp treats ENOSYS like EOPNOTSUPP when skipping optional attribute preservation (WASI has no chmod/chown at all), reads timestamps via Metadata::accessed/modified instead of the filetime crate (which panics there), and only errors out of --reflink when explicitly requested rather than whenever it isn't Never.

Rebased onto main now that #13804 covers WASI symlink support separately.

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/retry (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/cut/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/tail-n0f (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/cp/link-heap is now passing!
Congrats! The gnu test tests/tail/pipe-f is now passing!

[sylvestre]

i am surprised that you didn't enable more tests in test_cp.rs ?!

[eduardomourar]

I avoided adding more coverage as it makes rebasing all the changes back in the original branch harder. As soon as the rest of improvements are merged into main, I will gradually try to fix the tests being skipped for WASI and, if possible, increase coverage as well.

[sylvestre]

I am sorry but it is a requirement. I don't land changes without tests

[eduardomourar]

Priority given to #13804. I have put this one to draft and will close it as soon as the necessary changes have been merged to main. I have only kept the fix missing from that other PR already merged into main.

[github-actions]

Binary size comparison:

Individual binary size comparison VS main (threshold: >=5% AND >=4 KB).

Total size of compared binaries: 153.09 MB (+904 KB, +0.58%)

Significant per-binary changes:
  expr     2.76 MB ->    3.65 MB  (+908 KB, +32.11%)

[sylvestre]

i am not a fan of this long list of deactivation of tests for wasi :/
maybe we should split test_cp.rs with test_cp_XX.rs, etc to avoid this

[eduardomourar]

i am not a fan of this long list of deactivation of tests for wasi :/ maybe we should split test_cp.rs with test_cp_XX.rs, etc to avoid this

I agree. Let me finish all the pending PRs to get WASI Preview 2 testing enabled. I will leave the test for cp in single file for now and evaluate when everything is merged into main if we can create a separate file only for WASI (both p1 and p2). My objective is to ensure most of the tests can be executed for WASI and not skip them.