Merge "Added noop unregisterReceiver to complement existing noop registerReceiver."

test-runner/src/android/test/IsolatedContext.java

@@ -86,6 +86,11 @@ public class IsolatedContext extends ContextWrapper {
         return null;
     }
 
+    @Override
+    public void unregisterReceiver(BroadcastReceiver receiver) {
+        // Ignore
+    }
+
     @Override
     public void sendBroadcast(Intent intent) {
         mBroadcastIntents.add(intent);