[DO NOT MERGE] Eliminate duplicate layers in A11yService#getWindows()

Fixes: 73904014
Test: using TestBack, ensure the attached bug is fixed
Change-Id: I097ca47563420d658cea083a3b6f8d5e7d02991c
(cherry picked from commit 8f0124190ac0386a9429724b5fdf8f491b8cad05)
2 files changed