Address AutoRevokeTest flakiness

For some reason uiAutomator sometimes fails to find permissions view despite
uidump reporting it's there.
This switches to use bare accessbility APIs instead to address a possibility
of race between uiAutomator and uiDump.

Test: atest AutoRevokeTest
Bug: 153607914
Change-Id: If99d381ff58ef881c5b838ec1c1ecbd5b34403a4
4 files changed