Add a quick path to start transient recents

This may save 30%+ of the time in startActivityAsUser. That skips
ActivityRecord creation, intent task resolving, general intent
flags checking, finds all task which can resume, etc.

Also add a permission check for transient launch which is only used
for starting recents.

Bug: 235323163
Test: Enable shell transition. Enter recents by swipe-up and check
      the value of LatencyTracker ACTION_START_RECENTS_ANIMATION
      is reduced.

Change-Id: Ibd5fbd7a5bec53fb7a6d60b15c08ffb3a763ef0e