util/build-gnu.sh: Bypass timeout/yes SIGPIPE handling bug

[drinkcat]

See #7252, both timeout and yes reset the SIGPIPE handler (actually, the Rust core does that), leading to trap_sigpipe_or_skip_ test:

(trap '' PIPE && timeout 10 yes |:) 2>&1 | grep 'Broken pipe'

to fail, causing 4 tests to be skipped.

I believe the intent here is to check if the OS supports SIGPIPE, so it probably makes sense to use System's timeout/yes here, and run the tests anyway (which, happen to pass).

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/env/env-signal-handler. tests/env/env-signal-handler is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/printf/printf-surprise. tests/printf/printf-surprise is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/seq/seq-epipe. tests/seq/seq-epipe is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/tail/pipe-f. tests/tail/pipe-f is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)

[drinkcat]

Weird, those 4 GNUtest failure didn't happen for me.

I cleaned up my local gnu repo and now I see them too, so I think they are real.

This is ok BTW, it's more accurate to mark those tests as FAILed than SKIPed IMHO.

[cakebaker]

Thanks!