Move fast copy functions into angle::Format. These tables were duplicated in D3D11 and D3D9, and would have to be further duplicated into Vulkan. BUG=angleproject:1455 Change-Id: Ice1b81417d7b14f933b61861c4a9997c260ef72e Reviewed-on: https://chromium-review.googlesource.com/367690 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>