Wait until activity is destroyed before finishing SessionLifecycleTest.

Test: cts-tradefed run commandAndExit cts-dev -m CtsAutoFillServiceTestCases -t android.autofillservice.cts.SessionLifecycleTest

Bug: 111622428
Bug: 37566627

Change-Id: I41cf1ee36b200a46fe69f219bb578b8c1c6a03ca
2 files changed