Vulkan:Level/Layer hash fix-up
Vulkan:Level/Layer hash fix-up

Simplify has function for level/layer of imageView and add
asserts to make sure that there won't be hash collisions.

Bug: angleproject:4651
Change-Id: I8ab86a4f3d7aa668ad2c08e61bd5fd57744fcd12
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2257265
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Reviewed-by: Shahbaz Youssefi <582eeec4f08a2ccd61e3ef52115e6e7c571582de@chromium.org>
Commit-Queue: Tobin Ehlis <c15ba1c6ec8841cd136fafb26b333b1f76c86fb4@google.com>

ppy/angle,ppy/angle,ppy/angle,ppy/angle