Bug 1112780. Recreate the RenderTargetView on demand. r=jgilbert

This avoids reusing the RenderTargetView across AcquireSync/ReleaseSync pairs
and fixes bug 1109718. It adds a ReleaseSync call to ANGLE
that causes it to invalidate the RenderTargetView.

--HG--
extra : rebase_source : 993a437f5d1e1bfda32ef995b09f216930f174e1