Fixes for animationEnd in AnimatedImageDrawable

Bug: 63908092
Test: Manual

If the animation is running on the render thread, post a message (in
JNI) to call the listener.

Use a weak reference in the native listener so that it does not create
a cycle.

Don't add a listener if it's already in the list. Remove the native
listener when the Java listeners are all removed.

Call onAnimationEnd when the animation is stopped manually.

Change-Id: I5dc070089fb1cf399ac3316292592f614f2738f0