surfaceflinger: pass RenderEngine into BufferLayerConsumer

Add RenderEngine::isCurrent to replace
BufferLayerConsumer::checkAndUpdateEglStateLocked.  Remove a
duplicated check in updateAndReleaseLocked.  Use
RenderEngine::checkErrors.

Test: SurfaceFlinger_test
Change-Id: I6b97534a41a855d101965b498cb1afa72404227e
5 files changed