tests/run-multitests.py: Use LAN for IP address if WLAN doesn't exist.

This allows running the test on boards with just a LAN interface.

Fixes issue #8681.

tests/run-multitests.py

@@ -64,7 +64,10 @@ class multitest:
     def get_network_ip():
         try:
             import network
+            if hasattr(network, "WLAN"):
                 ip = network.WLAN().ifconfig()[0]
+            else:
+                ip = network.LAN().ifconfig()[0]
         except:
             ip = HOST_IP
         return ip