EFB copies that should be rendered fullscreen instead mess up the HUD

[CarlKenner]

We need to remember where the EFB was copied from, then recognise when EFB copies are being used as a texture (fairly easy because they are already handled specially), then change the projection when drawing them. But we need to be careful not to do that with projection shadows and other effects. Maybe we should also check if the region was cleared after we copied it (easy), because that implies that it is probably not a screen-space effect.