Unflake MediaControllerListenerTest and MediaBrowserListenerTest

Addressing flakiness of `recursiveChangesFromListeners_reportConsistentValuesForAllListeners` and
`onEvents_whenNewCommandIsCalledInsideOnEvents_isCalledFromNewLooperIterationSet`

The test did not have any way to avoid that events are added to the list
to assert after the count down latch was counted down. This created either
failing asserts or a `ConcurrentModificationException`. Making sure to not
produce further events or to not add further events to the data structure
that is later used for asserting fixes the problem.

PiperOrigin-RevId: 786257610

Author: marcbaechinger

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerListenerTest.java

@@ -3931,9 +3931,14 @@ public void onShuffleModeEnabledChanged(boolean shuffleModeEnabled) {
 
           @Override
           public void onEvents(Player player, Player.Events events) {
-            // onEvents is called twice.
-            eventsList.add(events);
-            controller.setShuffleModeEnabled(true);
+            if (latch.getCount() > 0) {
+              eventsList.add(events);
+              if (events.contains(Player.EVENT_REPEAT_MODE_CHANGED)) {
+                // This event is expected to be delivered in the next listener iteration processed
+                // in a following Looper task.
+                controller.setShuffleModeEnabled(true);
+              }
+            }
             latch.countDown();
           }
         };
@@ -4111,9 +4116,12 @@ public void recursiveChangesFromListeners_reportConsistentValuesForAllListeners(
         new Player.Listener() {
           @Override
           public void onPlaybackStateChanged(@Player.State int playbackState) {
-            listener1States.add(playbackState);
-            if (playbackState == Player.STATE_READY) {
-              controller.stop();
+            if (latch.getCount() > 0) {
+              // avoid trailing events making the test flaky
+              listener1States.add(playbackState);
+              if (playbackState == Player.STATE_READY) {
+                controller.stop();
+              }
             }
             latch.countDown();
           }
@@ -4122,7 +4130,10 @@ public void onPlaybackStateChanged(@Player.State int playbackState) {
         new Player.Listener() {
           @Override
           public void onPlaybackStateChanged(@Player.State int playbackState) {
-            listener2States.add(playbackState);
+            if (latch.getCount() > 0) {
+              // avoid trailing events making the test flaky
+              listener2States.add(playbackState);
+            }
             latch.countDown();
           }
         };