Add missing override for reevaluateBuffer in FakeAdaptiveMediaPeriod.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=180538379

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveMediaPeriod.java

@@ -96,6 +96,12 @@ public class FakeAdaptiveMediaPeriod extends FakeMediaPeriod
     }
   }
 
+  @Override
+  public void reevaluateBuffer(long positionUs) {
+    super.reevaluateBuffer(positionUs);
+    sequenceableLoader.reevaluateBuffer(positionUs);
+  }
+
   @Override
   public long getBufferedPositionUs() {
     super.getBufferedPositionUs();