Move UmaskGuard in uucore and use it for mkdir, mkfifo & mknod

[sylvestre]

followup of #10036

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing sylvestre:followup-10036 (64c9dda) with main (938039e)}

Summary

✅ 142 untouched benchmarks
⏩ 180 skipped benchmarks¹

Footnotes

1. 180 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/shuf/shuf-reservoir (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/sort/sort-stale-thread-mem (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/ptx/ptx-overrun is no longer failing!

[ChrisDryden]

This test is failing because the coverage tests use -Cpanic=abort so they don't have catch_unwind

You can add:

#[cfg(panic = "unwind")]

[ChrisDryden]

I think we have to be careful adding umask integration tests when its running multi-threaded because the UMaskGuard affects the process, when stress testing it the tests were flaky. Maybe adding a Mutex in the unit tests?

Might be good to add a comment in the helper function:

  /// Note: umask is process-wide, so this guard is not thread-safe.
  /// Concurrent use from multiple threads will cause race conditions.

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/shuf/shuf-reservoir (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/sort/sort-stale-thread-mem (passes in this run but fails in the 'main' branch)