Fix the issue when the sequence of PTS is out of order by bidirectional…

Fix the issue when the sequence of PTS is out of order by bidirectional prediction for skipToKeyframeBefore()

library/src/main/java/com/google/android/exoplayer2/extractor/DefaultTrackOutput.java

@@ -786,9 +786,7 @@ public final class DefaultTrackOutput implements TrackOutput {
         return C.POSITION_UNSET;
       }
 
-      int lastWriteIndex = (relativeWriteIndex == 0 ? capacity : relativeWriteIndex) - 1;
-      long lastTimeUs = timesUs[lastWriteIndex];
-      if (timeUs > lastTimeUs) {
+      if (timeUs > largestQueuedTimestampUs) {
         return C.POSITION_UNSET;
       }