graphics: ignore/reduce spurious vsync in VTS

Bug: 62802718
Test: VTS
Change-Id: I1ed73e0b2f14414f540865a96e6bd5ac1599fbf3
diff --git a/graphics/composer/2.1/vts/functional/GraphicsComposerCallback.h b/graphics/composer/2.1/vts/functional/GraphicsComposerCallback.h
index ada7d09..e332086 100644
--- a/graphics/composer/2.1/vts/functional/GraphicsComposerCallback.h
+++ b/graphics/composer/2.1/vts/functional/GraphicsComposerCallback.h
@@ -51,7 +51,7 @@
   // the set of all currently connected displays
   std::unordered_set<Display> mDisplays;
   // true only when vsync is enabled
-  bool mVsyncAllowed = false;
+  bool mVsyncAllowed = true;
 
   // track invalid callbacks
   int mInvalidHotplugCount = 0;