fix Simplify pathop fuzz

Simplify was out of sync with Op, and needed
to return failure when contour could not be
followed.

Also fix timeout where coincident detection
got stuck.

R=kjlubick@google.com

Bug:898114
Change-Id: Ia9076b9fd48e093bcc40ef21809c8eabe4cb9367
Reviewed-on: https://skia-review.googlesource.com/c/164601
Commit-Queue: Cary Clark <caryclark@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Auto-Submit: Cary Clark <caryclark@skia.org>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
diff --git a/src/pathops/SkPathOpsSimplify.cpp b/src/pathops/SkPathOpsSimplify.cpp
index 86b2c06..b6d7b40 100644
--- a/src/pathops/SkPathOpsSimplify.cpp
+++ b/src/pathops/SkPathOpsSimplify.cpp
@@ -57,7 +57,9 @@
                 writer->finishContour();
             } else {
                 SkOpSpanBase* last;
-                SkAssertResult(current->markAndChaseDone(start, end, &last));
+                 if (!current->markAndChaseDone(start, end, &last)) {
+                    return false;
+                }
                 if (last && !last->chased()) {
                     last->setChased(true);
                     SkASSERT(!SkPathOpsDebug::ChaseContains(chase, last));