selftests/net: packetdrill: more xfail changes (and a correction)

Recent change to add more cases to XFAIL has a broken regex,
the matching needs a real regex not a glob pattern.

While at it add the cases Willem pointed out during review.

Fixes: 3030e3d5 ("selftests/net: packetdrill: make tcp buf limited timing tests benign")
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250121143423.215261-1-kuba@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>