WIP nl: testing performance optimizations

[ChrisDryden]

For reviewers, I am mainly pushing this in its current state to view the codspeed analysis. not ready for a review yet

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail/inotify-dir-recreate is now passing!

[codspeed-hq]

CodSpeed Performance Report

Merging #9680 will improve performances by ×2.3

_{Comparing ChrisDryden:nl-performance-fixes (9c1ab6b) with main (a33c944)}

Summary

⚡ 2 improvements
✅ 125 untouched
⏩ 6 skipped¹

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	nl_large_file[10]	57.1 ms	25.6 ms	×2.2
⚡	nl_many_lines[100000]	44.9 ms	19.8 ms	×2.3

Footnotes

1. 6 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. ↩

[sylvestre]

@ChrisDryden do you have plan to finish this? thanks

[ChrisDryden]

Going to close this for now, I was hoping to prioritize the other open ones