Fix tail -c panics when requested bytes exceed file size

[dhr412]

This supersedes PR #10211 which was closed accidentally
Closes #10183

[dhr412]

@ChrisDryden Is the test okay now?

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will degrade performance by 3.96%

_{Comparing dhr412:main (6dc4ae5) with main (a1545ef)}

Summary

❌ 2 regressed benchmarks
✅ 280 untouched benchmarks
⏩ 38 skipped benchmarks¹

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

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Memory	cp_large_file[16]	115.3 KB	120.1 KB	-3.96%
❌	Memory	numfmt_large_numbers_si[10000]	4.6 MB	4.8 MB	-3.92%

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:

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

[ChrisDryden]

Thanks!