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
diff --git a/services/surfaceflinger/Scheduler/VSyncModulator.h b/services/surfaceflinger/Scheduler/VSyncModulator.h
index d7ec733..0bf3ceb 100644
--- a/services/surfaceflinger/Scheduler/VSyncModulator.h
+++ b/services/surfaceflinger/Scheduler/VSyncModulator.h
@@ -124,7 +124,7 @@
             changed = true;
         }
         if (desired.app != current.app) {
-            if (mSfConnectionHandle != nullptr) {
+            if (mAppConnectionHandle != nullptr) {
                 mScheduler->setPhaseOffset(mAppConnectionHandle, desired.app);
             } else {
                 mAppEventThread->setPhaseOffset(desired.app);