SF: add VSyncPredictor implementation

Adds an implementation of VSyncPredictor, an object that will
predict vsync events for multiple fixed-rate vsync systems.
The prediction is based on both the HWVsync signal and the
presentation fence timings for the VSyncDispatch object.

Bug: 140201379
Fixes: 140302888
Test: 13 new unit tests

Change-Id: I195902cc70561d028741d822e4001ad21ab391cf