Add support for @const to builtins in intrinsics.def.
Propagate this flag through to the intrinsic table.
Handle builtins that are @const annotated in the resolver.
Currently no intrinsics are decorated with @const, so there's nothing to
test (yet).
Bug: tint:1504
Change-Id: I172483688617782bd7c58b70e3f38d0222a5d1af
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/92323
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
451eee0fed