Fix start time modification outside of updatePlayTime()

BUG: 35340235
Test: manually start the chrome photos app, no crash
      and CTS at: ag/1908702

Change-Id: I3c0a6f140ee497020b562f25cade241dcd993c2a

core/java/android/animation/AnimatorSet.java

@@ -1865,7 +1865,7 @@ public final class AnimatorSet extends Animator implements AnimationHandler.Anim
             if (mEvent == ANIMATION_START) {
                 return mNode.mStartTime;
             } else if (mEvent == ANIMATION_DELAY_ENDED) {
-                return mNode.mStartTime = mNode.mStartTime == DURATION_INFINITE
+                return mNode.mStartTime == DURATION_INFINITE
                         ? DURATION_INFINITE : mNode.mStartTime + mNode.mAnimation.getStartDelay();
             } else {
                 return mNode.mEndTime;