Fix some cases when enabling hierarchical animation

- Fix split-screen primary stack's thumbnail won't animate:
    - in ActivityRecord#attachThumbnailAnimation, using WC#getAnimatingContainer
      to align the current animating layer.

- Fix animation surface position shifted when launching activity in
  split-screen secondary stack:
    - Using WC#getRelativeDisplayedPosition in WC#getAnimationAdapter
    to get relative position of leash parent.

Also, refined below logics:
- Refine logics in WindowContainer#getAnimationBounds with
  getDisplayBounds for fixing a regression issue that launching activity
  from split screen secondary stack the animation will moving to top stack rather
  then moving to bottom stack.

Bug: 142617871
Bug: 131661052

Test: Refectoring CL, all existing tests passed.
Test: Manual testing for:
      1) Enable hierarchical animation flag by using adb command:
         adb shell setprop persist.wm.hierarchical_animations 1
      2) Entering split-screen mode from recents app.
      3) Make sure task scroll-up thumbnail animation for split-screen primary
         stack can animated.
      4) Launch app to split-screen secondary stack, make sure launching
      animation position will right below divider instead going to top-side
      of screen.

Change-Id: I3ccc39ab1f3f02cecff8631512dc94f2f01c4be3