Increase UDP test timeout to 1200s

This is because the ESP8266 is now waiting for SEND OK and takes much
more to complete the send_repeat, and echo_burst tests in RAAS.
(but has higher pass ratio).

Author: michalpasztamobica

TESTS/netsocket/udp/udp_tests.h

@@ -48,7 +48,7 @@ static const int TESTS_TIMEOUT = MBED_GREENTEA_TEST_UDPSOCKET_TIMEOUT_S;
 #if MBED_CONF_TARGET_NETWORK_DEFAULT_INTERFACE_TYPE == MESH && MBED_CONF_NSAPI_DEFAULT_MESH_TYPE == WISUN
 static const int TESTS_TIMEOUT = (25 * 60);
 #else
-static const int TESTS_TIMEOUT = (10 * 60);
+static const int TESTS_TIMEOUT = (20 * 60);
 #endif
 #endif