mkfifo: drop path-based chmod to close TOCTOU race (#10020)

[sylvestre]

No description provided.

[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/rm/isatty (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/dd/no-allocate is now being skipped but was previously passing.
Congrats! The gnu test tests/tail/tail-n0f is now passing!

[codspeed-hq]

Merging this PR will improve performance by 4.12%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 312 untouched benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	sort_long_line[10000]	424.2 µs	407.4 µs	+4.12%

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_{Comparing sylvestre:toctou-mkfifo (2fc1822) with main (d928f05)}

Footnotes

1. 46 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. ↩

[RenjiSann]

Ci is sad :/