This significantly simplifies the calling code from Dawn.
It does require moving the SingleEntryPoint transform above the
renamer, since we need to call SEP with the original name. That is
probably also an optimization, since we do the subsequent transforms
with a culled AST.
Bug: tint:1268
Change-Id: I1f48ec0238ea76310742c60b119311747dd3dbac
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/80020
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>