SurfaceFlinger: some bug fixes on Scheduler

 - use mHWVsyncAvailable from Scheduler instead of SF
 - call DispSync::dump() on Scheduler
 - Revert VSYNC-app and VSYNC-sf names as systrace expects these
   names for vsync events

Test: run some applications
Change-Id: Ida0ba67eee55471d1df7f5e89a7b2ad36ab7074d
4 files changed