This CL adds BlockStatement support to the spirv-writer. The type
determiner is also updated as needed.
Bug: tint:134
Change-Id: I91e08c3acafd67401a010fff21abde7feec46e8e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/25609
Reviewed-by: Sarah Mashayekhi <sarahmashay@google.com>
dan sinclair