Revert "Avoid creating new instance on top when started for resu..."

Revert "Add tests for start singleTop/singleInstance activity fo..."

Revert submission 10112771-single-for-result

Reason for revert: b/149877125
Reverted Changes:
I923a0d9aa:Avoid creating new instance on top when started fo...
I7d47580f8:Add tests for start singleTop/singleInstance activ...

Change-Id: Ice262d1b8cada3b6c6fe0a5e8000bb59e0536596