This PR condenses the namespaces in the tint/utils folder.
Change-Id: I6b541a6383386346a0b11ba46074a5981fe75f66
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/86028
Auto-Submit: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>