timeout: add support for -f and -p short options

[cakebaker]

This PR adds support for -f and -p. These short options have been added in GNU timeout 9.6. From the release notes:

timeout now supports the POSIX:2024 specified -f, and -p short options,
corresponding to --foreground, and --preserve-status respectively.

The PR also simplifies some tests by using no_output() instead of no_stderr() and no_stdout().

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/misc/stdbuf (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/misc/usage_vs_getopt (passes in this run but fails in the 'main' branch)