This allows the value to be declared in a `const` expression, and to use arithmetic.
Fixed: tint:1636
Change-Id: Ie641a9d4183429c79c91605cd4df78f569be3579
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/105623
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>