All writers implemented, along with resolving and validation.
TODO: SPIR-V Reader.
Bug: tint:1330
Change-Id: I8ba2f6023749474f80efb8a5422ac187e6c73a69
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/71820
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Ben Clayton <bclayton@google.com>