sort: add benchmark for locale UTF-8 sorting

[sylvestre]

No description provided.

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/date/resolution (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/env/env-signal-handler was skipped on 'main' but is now failing.

[xtqqczze]

I just learnt divan doesn't perform warmup: nvzqz/divan#17

[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
🆕 4 new benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
🆕	Memory	sort_very_long_lines_utf8_locale	N/A	36 MB	N/A
🆕	Memory	sort_long_common_prefix_utf8_locale	N/A	628.7 KB	N/A
🆕	Simulation	sort_very_long_lines_utf8_locale	N/A	54.2 ms	N/A
🆕	Simulation	sort_long_common_prefix_utf8_locale	N/A	919.8 µs	N/A
⚡	Simulation	sort_long_line[10000]	424.2 µs	407.4 µs	+4.12%

---

_{Comparing sylvestre:sort-per-bench (91c970e) with main (980f269)}

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. ↩

[xtqqczze]

Closes #12150?