Tweak verifyApplicationThread to compare Threads, not Loopers

#minor-release

PiperOrigin-RevId: 371306241

library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java

@@ -2016,7 +2016,7 @@ public class SimpleExoPlayer extends BasePlayer
     // The constructor may be executed on a background thread. Wait with accessing the player from
     // the app thread until the constructor finished executing.
     constructorFinished.blockUninterruptible();
-    if (Looper.myLooper() != getApplicationLooper()) {
+    if (Thread.currentThread() != getApplicationLooper().getThread()) {
       String message =
           Util.formatInvariant(
               "Player is accessed on the wrong thread.\n"