Crop windowing layer for shell rotation animation

This aligns the behavior as legacy rotation animation in commit db7097e5.
Note that the crop will be cleared in finishTransaction set from core's
Transition#buildFinishTransaction.

Also clean some fields a bit.

Bug: 242664636
Test: Enable launcher rotation. Set animation scale to 10x.
      Rotate display and observe that the wallpaper does not exceed
      the area of previous display size.
Change-Id: Ie2144f7c19663b573167de819dde01cc9eca7ad4