Revert "Initial checkin of GM verifier framework"

This reverts commit 7e36f0015e13441f6dd342f142d431dcf830e5e9.

Reason for revert: breaking google3 roll

Original change's description:
> Initial checkin of GM verifier framework
> 
> The goal of the verifier framework is to enable opt-in checks of the
> images produced by individual GMs. The basis of verification will be
> comparing the rendered output of a GM against a source-of-truth image,
> such as one generated by the CPU backend.
> 
> In the short term this can enable coarse-grained sanity checks for a
> subset of GMs to catch e.g. egregious rendering bugs. In the longer term
> this can provide an SkQP-style suite of tests that can be run across
> many/all GMs to provide a vote of confidence in the rendering
> correctness of new devices.
> 
> Bug: skia:9855
> Change-Id: Id7310de8005ffa7e8eb2fd0e4008f5f8db1419ab
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/267761
> Commit-Queue: Derek Sollenberger <djsollen@google.com>
> Auto-Submit: Tyler Denniston <tdenniston@google.com>
> Reviewed-by: Derek Sollenberger <djsollen@google.com>

TBR=djsollen@google.com,tdenniston@google.com

Change-Id: Ie3beff447fea406b5ad3c3ca5a98fa2bd73d20fb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:9855
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268682
Reviewed-by: Tyler Denniston <tdenniston@google.com>
Commit-Queue: Tyler Denniston <tdenniston@google.com>
8 files changed