Avoid -Wswitch warnings in wxWebRequest test

No real changes, just suppress the warnings about not handling all
states in a switch.

tests/net/webrequest.cpp

@@ -75,6 +75,10 @@ public:
         case wxWebRequest::State_Cancelled:
             loop.Exit();
             break;
+
+        case wxWebRequest::State_Idle:
+        case wxWebRequest::State_Active:
+            break;
         }
     }