dd,df: fix out-of-bounds panic in suffix selection loop

[devnexen]

The bounds check was evaluated after the array access due to short-circuit evaluation order, and used the wrong upper bound, allowing the index to exceed the suffixes array length.

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail/tail-n0f is now passing!

[sylvestre]

please add test to make sure we don't regress in the future
thanks

[sylvestre]

i was more thinking about the error that you could trigger from df or dd directly ?

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/pr/bounded-memory. tests/pr/bounded-memory is passing on 'main'. Maybe you have to rebase?
Congrats! The gnu test tests/tail/tail-n0f is now passing!

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/usage_vs_getopt (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/shuf/shuf-reservoir (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/sort/sort-stale-thread-mem (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/tail/tail-n0f is now passing!

[codspeed-hq]

Merging this PR will improve performance by 3.87%

⚡ 1 improved benchmark
✅ 283 untouched benchmarks
⏩ 38 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	sort_ascii_utf8_locale	18 ms	17.3 ms	+3.87%

---

_{Comparing devnexen:dd_df_out_of_bounds (6703990) with main (ec7e81e)}

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. ↩

[ChrisDryden]

If my understanding is correct, this would only trigger when a file was 999 Yottabytes, so I don't think we will be able to make a regression test for this one 😄

[github-actions]

GNU testsuite comparison:

Note: The gnu test tests/expand/bounded-memory is now being skipped but was previously passing.