SurfaceFlinger: use intended wake up time when calculating next present time

If SurfaceFlinger wakes up too late (due to the main thread being busy)
it may calculate a wrong presentation time as it is based on the wake up time.
Instead, cache the intended wake up time and use it as the base time.

Change-Id: I84c37bd5f164fbdef3151c0898d3cea624cea515
Bug: 154199567
Test: collect systrace for launcher scrolling
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 6995ee0..e96fba7 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -319,7 +319,7 @@
         return mFlinger->setPowerModeInternal(display, mode);
     }
 
-    auto onMessageReceived(int32_t what) { return mFlinger->onMessageReceived(what); }
+    auto onMessageReceived(int32_t what) { return mFlinger->onMessageReceived(what, systemTime()); }
 
     auto captureScreenImplLocked(
             const RenderArea& renderArea, SurfaceFlinger::TraverseLayersFunction traverseLayers,