Make Settings robotest work with tot Robolectric

Bug: 116278591
Test: make -j RunSettingsRoboTests
Change-Id: I32cb2fcf6094675f79d2fc24702ef6298a9691e4

tests/robotests/src/com/android/settings/sound/MediaOutputPreferenceControllerTest.java

@@ -165,7 +165,6 @@ public class MediaOutputPreferenceControllerTest {
     @After
     public void tearDown() {
         mShadowAudioManager.reset();
-        mShadowMediaRouter.reset();
         ShadowBluetoothUtils.reset();
     }