This adds call to release UDP port in a timely manner, so they can be
reused in subsequent tests. Otherwise, one could face issue like #17623.
Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>
Some targets (eg PYBV10) have the socket module but are unable to create
UDP sockets without a registered NIC. So skip UDP tests on these targets.
Signed-off-by: Damien George <damien@micropython.org>