Choreographer: Add disable VSync for CPU Rendered apps

Choreographer VSync has some performance impact for CPU rendered apps as the
app has to wait for VSync to start a new frame draw. When the frame draw time
exceeds one VSync, this has a direct impact on the FPS.

Add a feature to disable VSync for CPU rendered apps using system property.

"debug.cpurend.vsync" property controls the VSync for CPU rendered apps.
This is set to true by default to maintain upstream behavior. To disable VSync
for CPU rendered app, the property is set to false.

Change-Id: If302c003ddfa57b4b45d8ebbb9b241a049eb32c8