Fix import order in JavaTest.java.tmpl

This was mistakenly forgotten in #1596.

Author: hoisie

testing/templates/JavaTest.java.tmpl

@@ -1,12 +1,12 @@
 package com.google.firebase.test;
 
 import android.app.Activity;
-import org.robolectric.RobolectricTestRunner;
 import org.junit.Assert;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 import org.junit.runner.RunWith;
 import org.robolectric.Robolectric;
+import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
 /** A test wrapper that wraps around native C++ code that calls RUN_ALL_TESTS(). */