need conservative bounds for triangles due to SkFixed drift in SkEdge

Bug: oss-fuzz:8018
Change-Id: I09456f906b7eb89f74ffd2c484bc6e30e029bfbb
Reviewed-on: https://skia-review.googlesource.com/131021
Reviewed-by: Cary Clark <caryclark@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed