WM: Cleanup TestAppWindowToken code and clean up mocktracker in teardown

- Followup from commit:aab3d3d7 to not skip onParentChanged when creating TestAppWindowToken.
- This is not needed since we are mocking SurfaceControl and Transaction native calls by
  default.
- Lastly, always clean up mocktracker if there is an exception thrown in WindowTestsBase#tearDownBase

Bug: 127948929
Test: atest WmTests
Change-Id: I17af51d8cf2caeda699ece0c945e9f8c04f88015