fix pathmeasure fuzz

distanceToSegment can return NaN

R=kjlubick@google.com

Bug: skia:
Change-Id: Iaafe5712bbf416058c8c5066a46300858c12ce4b
Reviewed-on: https://skia-review.googlesource.com/153494
Auto-Submit: Cary Clark <caryclark@skia.org>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
1 file changed