meta/copy_image: Stash off the scissor
The meta CopyImageSubData path uses BlitFramebuffers to do the actual copy. The only thing that can affect BlitFramebuffers other than the currently bound framebuffers is the scissor so we need to save that off and reset it. If we don't do this, applications that use a scissor together with CopyImageSubData will get accidentally scissored copies. Tested-by: Markus Wick <markus at selfnet.de> Reviewed-by:Anuj Phogat <anuj.phogat@gmail.com> (cherry picked from commit 736c6f3c)