Remove gamut GM

This was based on old ideas about color management. We have better
mechanisms for testing this now.

Bug: skia:
Change-Id: If59b5039f31ab0ebbdbed4205c941dd9266f67c1
Reviewed-on: https://skia-review.googlesource.com/c/172860
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
7 files changed