dan sinclair c214cbe98b Add a none format.
This CL adds a `none` format to the tint command in order to allow
skipping the emission of the resulting program. This adds a `unknown`
format to take the place of the original `none`.

Change-Id: Ib25e933857c0acb26e3cf0e04ed8a5d1cca1e633
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/110480
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
2022-11-16 22:29:12 +00:00
..
2022-11-16 22:29:12 +00:00