https://github.com/gpuweb/gpuweb/issues/3056 proposes that creation-time
constant expressions should support arrays. We have verbal agreement to
update to spec to support const arrays.
Bug: tint:1580
Change-Id: If460f729384d700a1c2149c5b7dbe8613a960184
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/94330
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>