Use LatencyTracker to log the time of recents animation

The ACTION_TOGGLE_RECENTS on launcher side may be not close enough
to the user feeling because it cannot know the actual window drawn
time on system. And it may be mixed with 3 button navigation mode
which doesn't start recents animation. So here creates a new latency
type to log the case of recents animation explicitly.

Bug: 169221287
Test: Use gesture navigation mode and swipe up from an app. The log
      will show "LatencyTracker: action=8 latency=xx".
Change-Id: I660f472113684590b4eba40c0534da9dcf7773ce