This is done via a new extension, which in the future could also be
used by shader authors as an escape hatch while we are still refining
the analysis.
The transform is run by the sanitizers for all of the non-WGSL
backends.
Bug: tint:880
Change-Id: Ibe90d7437d34c741a91eda65dff6d21d8469b9c7
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/88464
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
