readlink: Set silent mode as default

[denendaden]

This primarily changes readlink to be silent rather than verbose by default, in accordance with GNU readlink. It also makes a couple more minor changes, to bring behavior in line with GNU:

• -s, -v, and -q can now be duplicated, and the last one takes priority
• when POSIXLY_CORRECT is set, -s and -q are ignored entirely and it is always verbose (I am not sure if this is intentional behavior on GNU's part but it is how it currently seems to work)

Fixes #10578

[sylvestre]

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

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/inotify-dir-recreate (passes in this run but fails in the 'main' branch)

[ChrisDryden]

Seems like the windows tests are failing because its expecting the platform specific error message:

.stderr_contains("Invalid argument")