Release ads loader on new intent in the demo app

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=208056265

demos/main/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -207,6 +207,7 @@ public class PlayerActivity extends Activity
   @Override
   public void onNewIntent(Intent intent) {
     releasePlayer();
+    releaseAdsLoader();
     clearStartPosition();
     setIntent(intent);
   }