Uses SF callback windows for the A11yWindowInfo [2/n]

1. The SF callbacks the windows even they are in the transition state.
This will make many useless A11y events reporting to the A11y services,
like windows change with bounds change event. To avoid this symptom,
we assume the callback windows become stable and compute the reported
windows to the A11y framework if the SF callback isn't sent within 2
frames time (about 35ms).

2. To avoid the endless SF callback always in a short time, then A11y
framework can't obtain any windows, we set a maximum time, 500ms, which
is longer than the whole animation, to compute the reported windows.

3. Removes the legacy signals from the WM to compute the reported
windows due to they can be covered by the signals from the SF callback.

Bug: 191736824
Test: a11y CTS & unit tests
Test: Manual testing including the A11y services
Change-Id: Ibe2096e388769a12e3bcbaa472239ec9e458a396