D3D11: Merge d3d11::TextureFormat and ANGLEFormatSet. BUG=angleproject:1455 Change-Id: I7fc2640ec9d73528feb526b4d8b89cabccda4d17 Reviewed-on: https://chromium-review.googlesource.com/367092 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>