There's now no need to have both.
Removes a whole bunch of Sem().Get() smell, and simplifies the resolver.
Also fixes a long-standing issue where an array with an explicit, but equal-to-implicit-stride attribute would result in a different type to an array without the decoration.
Bug: tint:724
Fixed: tint:782
Change-Id: I0202459009cd45be427cdb621993a5a3b07ff51e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/50301
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>