Reject degenerate quads in AA hairline path renderer

Includes unit test that reproduces the original bug.

Bug: chromium:1232834
Change-Id: Iae2f52b42d35f0774c4cf9fa686df7aaf57c130a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/433279
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed