Merge branch 'af_unix-fix-bunch-of-msg_oob-bugs-and-add-new-tests'

Kuniyuki Iwashima says:

====================
af_unix: Fix bunch of MSG_OOB bugs and add new tests.

This series rewrites the selftest for AF_UNIX MSG_OOB and fixes
bunch of bugs that AF_UNIX behaves differently compared to TCP.

Note that the test discovered few more bugs in TCP side, which
will be fixed in another series.
====================

Link: https://lore.kernel.org/r/20240625013645.45034-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>