tests/extmod: Skip select/socket tests if they can't create UDP socket.

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>

tests/extmod/select_poll_udp.py

@@ -8,9 +8,13 @@ except (ImportError, AttributeError):
     print("SKIP")
     raise SystemExit
 
+try:
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+except OSError:
+    print("SKIP")
+    raise SystemExit
 
-s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
 poll = select.poll()
 
 # UDP socket should not be readable

tests/extmod/socket_udp_nonblock.py

@@ -6,9 +6,13 @@ except ImportError:
     print("SKIP")
     raise SystemExit
 
+try:
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+except OSError:
+    print("SKIP")
+    raise SystemExit
 
-s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
 s.settimeout(0)
 
 try: