t/connect: Don't use a static port number

Don't use a static port number. It might already be in use, resulting
in a test failure. Use an ephemeral port to make this test reliable.

Cc: Dylan Yudaken <dylany@fb.com>
Cc: Facebook Kernel Team <kernel-team@fb.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Tested-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Link: https://lore.kernel.org/r/20220902071153.3168814-9-ammar.faizi@intel.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>