bench(shuf): add short average line length benchmarks

[xtqqczze]

No description provided.

[xtqqczze]

@sylvestre please could you review

[sylvestre]

sorry, i missed it
why do you see values in having several data size?
often, it is linear

[xtqqczze]

why do you see values in having several data size?

We allocate memory based on an estimated line length, but the current implementation is possibly overly tuned to a specific line length.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/misc/tty-eof. tests/misc/tty-eof is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Note: The gnu test tests/tail/pipe-f is now being skipped but was previously passing.
Note: The gnu test tests/tail/tail-n0f is now being skipped but was previously passing.
Congrats! The gnu test tests/unexpand/bounded-memory is now passing!
Skip an intermittent issue tests/pr/bounded-memory (was skipped on 'main', now failing)