Fix stencil reference value used in Dawn backend and enable unit test.
The "user" reference value was being used rather than the resovled
value.
Also set the cap that two sided stenciling doesn't support separate
mask and ref values (like D3D).
Enable the recently added unit test crbug_1271431 which was failing
because of this bug.
Bug: skia:12675
Change-Id: I49d2443d8f7855706f98f59553bb7ca86f336f23
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/475640
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
4 files changed
