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

[sylvestre]

followup of #10036

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will degrade performance by 3.66%

_{Comparing sylvestre:followup-10036 (40ce322) with main (ca13e33)}

Summary

⚡ 1 improved benchmark
❌ 2 regressed benchmarks
✅ 279 untouched benchmarks
⏩ 38 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Memory	du_wide_tree[(5000, 500)]	1.2 MB	1.3 MB	-3.66%
❌	Memory	dd_copy_partial	129.1 KB	133.4 KB	-3.21%
⚡	Memory	dd_copy_default	130.8 KB	126 KB	+3.78%

Footnotes

1. 38 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)