[Graphite] Remove CommandBufferTest.

It has served use well, but its time to let it enjoy its life in
retirement.

Change-Id: I47213a7a74a890aa0b04e906fb236c7cc4aabb61
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/550621
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Auto-Submit: Greg Daniel <egdaniel@google.com>
5 files changed