Instead of using builder.Diagnostics().contains_errors()
Produces cleaner code and reduces scope of error handling.
Bug: tint:1661
Change-Id: I35af5ad1c6553f2cf74d1ce92dc14984f93b9db4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/102161
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>