Allow transitioning through lifecycle when finished

When finish was requested for an activity, certain
lifecycle transitions were blocked to avoid delivering
invalid callbacks in the past. The checks and early
returns that were left from the old way of resolving
lifecycle cancelled delivering STARTED, RESUMED and
PAUSED state if an activity called finish().
This is no longer required with Lifecycler infrastructure
that takes care of ensuring validity of all transition
sequences.

Bug: 127106719
Bug: 126693030
Test: ActivityLifecycleTests#testFinishInOn*
Change-Id: I5ed006f1846e54589f33da0cab3b6f3bf9ca5a61