Change framework services tests' runner

Change the test runner to android.support.test.runner.AndroidJUnitRunner
This newer runner support Mockito tests. See b/8138651
This should at least fix RankingHelperTest here.

Change-Id: I68e4f33939478e1ea59a3860d5ded1cd22a47989
diff --git a/services/tests/servicestests/AndroidManifest.xml b/services/tests/servicestests/AndroidManifest.xml
index 919293a..386a9cb 100644
--- a/services/tests/servicestests/AndroidManifest.xml
+++ b/services/tests/servicestests/AndroidManifest.xml
@@ -69,7 +69,7 @@
     </application>
 
     <instrumentation
-    	android:name="android.test.InstrumentationTestRunner"
+    	android:name="android.support.test.runner.AndroidJUnitRunner"
     	android:targetPackage="com.android.frameworks.servicestests"
     	android:label="Frameworks Services Tests" />
 </manifest>