Fixes #10192 - fix(comm): improve stdout handling and add test for lossy UTF-8 output

[Paol0B]

This pull request refactors the output handling in the comm utility to write output directly to a locked stdout handle, improving efficiency and error handling, especially for non-UTF-8 input. It also adds a new test to ensure correct output when processing files with invalid UTF-8 sequences.

Output handling improvements:

• Changed from using print! macros to writing directly to a locked stdout handle via stdout.write_all, allowing for more efficient and robust output, particularly for non-UTF-8 data. All output operations now properly handle errors using map_err_context. (src/uu/comm/src/comm.rs) [1] [2] [3] [4] [5] [6]

Testing for non-UTF-8 input:

• Added a new test, test_output_lossy_utf8, to verify that the utility correctly handles and outputs files containing invalid UTF-8 bytes, matching GNU comm's behavior. (tests/by-util/test_comm.rs)

[github-actions]

GNU testsuite comparison:

Note: The gnu test tests/printf/printf-surprise is now being skipped but was previously passing.

[sylvestre]

please run cargo fmt

[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)

[Paol0B]

The current CI failure occurs during package installation on ubuntu-latest, prior to running any project-specific steps.
From the logs it appears related to external APT repositories returning 403.

[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)

[ChrisDryden]

As a side note for other reviewers, I felt that the way that the output was written was repetitive and that we should have made a helper function for that but it turns out that we do not have that implemented yet and there's many utilities that follow that same format. Would be great as a follow up task to make that format into a helper and cleaning up all of the ones that match that pattern.

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will improve performance by 8.42%

_{Comparing Paol0B:fix/10192 (ea47ce4) with main (5fd3459)}

Summary

⚡ 2 improved benchmarks
✅ 280 untouched benchmarks
⏩ 38 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Memory	du_deep_tree[(100, 3)]	155.8 KB	143.7 KB	+8.42%
⚡	Memory	numfmt_large_numbers_si[10000]	4.9 MB	4.7 MB	+4.01%

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. ↩