Fix ActivityVisibilityTests on Android TV

In testTurnScreenOnActivity, waiting all started activities are removed
is not done because Home activity is still existed.
Waiting all started activities should be applied with proper condition.

Bug: 309569041
Test: run cts -m CtsWindowManagerDeviceTestCases
      -t android.server.wm.ActivityVisibilityTests
Change-Id: I2458276b231b35c18e98ca60bab25d2985ceb60a
1 file changed