Roll Skia from b8e36741e07d to 2f6c53ff720a (4 revisions)

https://skia.googlesource.com/skia.git/+log/b8e36741e07d..2f6c53ff720a

2021-11-22 jvanverth@google.com [graphite] Add SkSL compiler support
2021-11-22 bsalomon@google.com Rebind GrGLRenderTarget if there is a lazy stencil attachment change.
2021-11-22 michaelludwig@google.com [graphite] Add vertex/instance attribute definition to RenderStep
2021-11-22 jvanverth@google.com Change SkSL::ShaderCaps and GrShaderCaps to structs.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://skia-autoroll.corp.goog/r/android-master-autoroll
Please CC djsollen@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Test: Presubmit checks will test this change.
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.
Bug: b/186777432
Change-Id: Ibc67679bd7754db97a428fbec761dba35cf46356