Fix ConcurrentModificationException in AnimatorSet.
Fix ConcurrentModificationException in AnimatorSet.

Would occur if you would start an AnimatorSet for the
second time.

Change-Id: I8fa0e8ab039e8525acae1564b2e9dec4a0838981

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base