Implement Relative Insets

This change implements the relative insets.

Relative insets is to describe the insets by the insets size based on
the window the insets attached, instead of any absolute coordinate on
the display. The shell before this change can only provide insets with
arbitrary frame coordinates and to resolve the synchronization issue, a
special policy was introduced to caption bar and caused many layout
issues.

This change allows the shell to provide insets with insets size. As the
caption bar is very likely to have a stable height to the window, even
after the window resizes, this method can avoid repeatedly insets update
from the shell to the WM server. Also, the calculation process is
improved to support this use case. Besides the frame used to calculate
the insets, additional window bounds was introduced. The insets size is
relative to the window bounds (task bounds) and the window bounds will
be used to have the calculation works correctly.

Unnecessary call to the insets change notification was removed when the
relative insets is introduced. No insets re-calculation is needed
anymore. This will also improve the performance during the window
resizing.

Test: InsetsStateTest InsetsPolicyTests
Test: InsetsSourceTest InsetsAnimationControlImplTest
Test: WindowContainerTests WindowDecorationTests
Flag: com.android.window.flags.relative_insets
Bug: 277292497

Change-Id: Id55cffba39c5ca2e1c2fd7c591e1d9e529c5901f