Make canBeImeTarget be compatible with legacy behavior

And let IME always extend into the status bar area so that the position
of IME can never affected by status bar. This can prevent flicker during
IME animation.

This CL also makes PerDisplay can restart the animation while the insets
source control is changed during animation.

Fix: 151759336
Test: atest WindowStateTests
Change-Id: Ic2a308e6b7ec39b4b8645751e31addd26ddf3735