Vulkan: Refactor format table. This moves the Vulkan format table to dynamically generated, but keeps it easily indexed. Because Vulkan format support is not able to be fully determined until runtime, we'll need a dynamic way to build the table. The most straight-forward way seems to be to keep a copy of the full table in the Renderer. Initializing it once at startup makes it a bit slower to init, but saves us from any threading shenanigans with lazy init when (and if) we ever support multi- threaded Contexts. BUG=angleproject:2207 Change-Id: Ib1ac879daa562c7ad1a965390be401fa2314e42c Reviewed-on: https://chromium-review.googlesource.com/742374 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org>