WM: Replace eEarlyWakeup flags with explicit eEarlyWakeup start and end flags

eEarlyWakeup flag is used as a hint to SurfaceFlinger to adjust its
offsets so it can wakeup earlier and have sufficient time to compose
more complex scenes.

This flag has been replaced with explicit start and stop flags which
ensure the SurfaceFlinger offsets remain consistent during animation.

Bug: 158127834
Test: go/wm-smoke
Test: systrace to verify new tracepoint and offset behavior

Change-Id: Ib9c35c01a6bf02f88ec7cb1778e01909bd2f9055