Just a minor cleanup; no functional change.
Change-Id: Iac4f97c2b5507f7665024885a81f6ccf8e5ab269
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/82440
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>