Disable mesh networking on tests by default

Testing a mesh requires proper environment.

tools/test_configs/config_paths.json

@@ -9,5 +9,6 @@
     "6LOWPAN_HOST" : "6lowpanInterface_host.json",
     "6LOWPAN_ROUTER" : "6lowpanInterface_router.json",
     "THREAD_END_DEVICE" : "ThreadInterface_end_device.json",
-    "THREAD_ROUTER" : "ThreadInterface_router.json"
+    "THREAD_ROUTER" : "ThreadInterface_router.json",
+    "NO_NETWORK": "no_network.json"
 }

tools/test_configs/no_network.json

@@ -0,0 +1,17 @@
+{
+    "config": {
+        "echo-server-addr" : {
+            "help" : "IP address of echo server",
+            "value" : null
+        },
+        "echo-server-port" : {
+            "help" : "Port of echo server",
+            "value" : null
+        }
+    },
+    "target_overrides": {
+        "*": {
+            "target.network-default-interface-type": null
+        }
+    }
+}

tools/test_configs/target_configs.json

@@ -44,7 +44,7 @@
         "test_configurations": ["IDW0XX1_WIFI"]
     },
     "KW24D": {
-        "default_test_configuration": "6LOWPAN_HOST",
+        "default_test_configuration": "NO_NETWORK",
         "test_configurations": ["6LOWPAN_HOST", "6LOWPAN_ROUTER", "THREAD_END_DEVICE", "THREAD_ROUTER"]
     }
 }