CGL/EAGL: Fix default FBO size on Retina displays This was found while trying to fix https://github.com/glfw/glfw/issues/1169 VulkanSurfaceMtl and metal/SurfaceMtl already handle contentsScale correctly. Change-Id: I234d7b0901dd7c075cf1e9d58466f52140ab1e2b Bug: None Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2154670 Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>