Avoid resuming same activity twice

Activity process was found to be dead and required to restart
its process while starting the activity. If the same activity
being restarted again before the new process started, the
activity would be finished because of a second failure.

Bug: 124125128
Test: atest android.server.am.lifecycle
Change-Id: Iad829d59a9d789b01b3570e6c1ff062fb2dc9a81