Fallback to moveTo when unable to find the first tangent in cubicTo

src/core/SkStroke.cpp

Index: src/core/SkStroke.cpp
diff --git a/src/core/SkStroke.cpp b/src/core/SkStroke.cpp
index b138c326bab497c96429ed1d111ff57954c8ab0d..1e4ae79a5e0108725d2492a268bdeac122e053bb 100644
--- a/src/core/SkStroke.cpp
+++ b/src/core/SkStroke.cpp
@@ -424,7 +424,8 @@ void SkPathStroker::cubicTo(const SkPoint& pt1, const SkPoint& pt2,
     bool    degenerateBC = SkPath::IsLineDegenerate(pt1, pt2);
     bool    degenerateCD = SkPath::IsLineDegenerate(pt2, pt3);
 
-    if (degenerateAB + degenerateBC + degenerateCD >= 2) {
+    if (degenerateAB + degenerateBC + degenerateCD >= 2
+            || (degenerateAB && SkPath::IsLineDegenerate(fPrevPt, pt2))) {
         this->lineTo(pt3);
         return;
     }