When these are used inside a function, we were not unwrapping the
array from the struct that we wrapped it in.
Fixed: tint:1385
Change-Id: Ide7bbd802394bf09819265be48d978ec9346adfe
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/77180
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: James Price <jrprice@google.com>
James Price