Restore correct app State when combing "-D" and "--suspend" flags

Starting an app in debug (-D), suspended (--suspend) mode will
result in the app unable to restore its initial state.

ActivityManagerService.setDebugApp has side effects. It saves a
state that is only restore later during the app booting. Calling
it twice in a row, "double saves" which resulting forgetting the
initial state.

Test: Manual
Bug: 266233210

Change-Id: I7819a3c0f7e46994548c584c4c5d61f6d24faf61