Add caps bit for 2x2 matrix comparison rewrites.

This will allow us to rewrite `mat == mat` on Adreno 5xx/6xx GPUs when
running in GLSL.

Change-Id: I621e918a545a49b7ecb9c944ae59b1e7a7594bae
Bug: skia:11308
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/410996
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
9 files changed