Exercise concave analytic AA

This will allow Skia trybots (e.g., 1M skp) to exercise analytic AA.
There's still a guard flag in Chromium that prevents layout tests failure.

TBR=reed@google.com,caryclark@google.com

BUG=skia:

Change-Id: Ie893c10d34bf969e013ef047c1bbf4b004d584cc
Reviewed-on: https://skia-review.googlesource.com/7091
Reviewed-by: Yuqian Li <liyuqian@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
2 files changed