AdapterService: Only clear sAdapterService once

Pass the current AdapterService to clearAdapterService().
Call cleanup() in the unit test.

Bug: 67460963
Test: Toggle Bluetooth
  runtest -j32 bluetooth -c com.android.bluetooth.btservice.AdapterServiceTest
Change-Id: Icdaac794e3cdb24d49b4727e762773fb58dd660c
2 files changed