Also adds a golden that depends on https://github.com/flutter/engine/pull/55270. Resolves https://github.com/flutter/flutter/issues/142731. Allow setting the stencil compare function, pass/fail operations, and read/write masks. Flutter GPU has light "shader object" style programs, so all of the stencil configuration state can be set on the `RenderPass` at any time. New simple golden that exercises stencil ops: 