A11y support for windows in a re-parented display

Currently, accessibility only supports windows in default display.
The windows in other displays aren't recongnized by accessibility
even they're re-parented to default display. Besides, we need to
offset the bound after re-parented since the original is from its
own display.

Bug: 129098348
Test: atest WindowStateTests
Test: atest DisplayContentTests
Test: a11y CTS & unit tests
Change-Id: I41a84a4c02e3c1be1dab4bd420d504b85787c4fb