Vulkan: Get rid of "fetch" level/layer image views. Instead always use 2D array views when rendering to cube maps. We need to keep the "fetch" image view for the main image for emulating seamless cube map textures on GL 2.0. We also use it for some texture copying init. These uses could potentially be replaced with sample instructions if we wanted to remove this last "fetch" view. Bug: angleproject:3975 Change-Id: I90f9be9fc6542d8ec27f6722132c1b27acf72176 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1842226 Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Cody Northrop <cnorthrop@google.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>