[SurfaceFlinger] Some dispsync fixes for early event firing

* Fix lastEventTime for listeners so that they don't fire early.
* Properly set mHasFired for listeners so that if the dispsync model
is currently being updated that mHasFired is always set to true
if lastEventTime is after the most recent vsync reference.

Bug: 132678707
Bug: 130684082
Test: systrace
Change-Id: I5b860336f12b742cc67665776290939b61e7e3af