Fix #10010: mv Cross-Device Symlink Fallback EEXIST

[minimoog]

When mv uses symlink across filesystems instead relinking (returns EEXITS), now rename_symlink_fallback tries, atomically, to recreate the link if it's across devices.

Added test_mv_cross_device_symlink_overwrite() to test this scenario.

[sylvestre]

please update the title of the PR

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/shuf/shuf-reservoir. tests/shuf/shuf-reservoir is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/sort/sort-stale-thread-mem. tests/sort/sort-stale-thread-mem is passing on 'main'. Maybe you have to rebase?

[minimoog]

I need to figure out how to test mv across device symlinks for WSL2, FreeBSD, OpenBSD and Android, since test is using /dev/shm as temp folder which works on Linux.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/sort/sort-stale-thread-mem. tests/sort/sort-stale-thread-mem is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/shuf/shuf-reservoir is no longer failing!
Congrats! The gnu test tests/sort/sort-stale-thread-mem is no longer failing!

[github-actions]

GNU testsuite comparison:

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

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)