xwayland: Store EGLContext pointer in lastGLContext (cherry pick to xwayland branch)
We were storing the pointer to struct glamor_context. However, glamor itself is storing the EGLContext pointer since the commit below. Since the two values could never be equal, this resulted in constant superfluous eglMakeCurrent calls. The implicit glFlush triggered by those couldn't be good for performance.
Fixes: 7c88977d "glamor: Store the actual EGL/GLX context pointer in lastGLContext" Reviewed-by: Olivier Fourdan ofourdan@redhat.com
(cherry picked from commit b656b0aa)