fix bugs found by computing flat clips in 800K skps

src/pathops/SkPathOpsTriangle.cpp

Index: src/pathops/SkPathOpsTriangle.cpp
diff --git a/src/pathops/SkPathOpsTriangle.cpp b/src/pathops/SkPathOpsTriangle.cpp
index 7db4831a06985e61555a2be539ad3a44d8f9ed80..77845e067309cd3d83f772f7dc8c0368abf6cecb 100644
--- a/src/pathops/SkPathOpsTriangle.cpp
+++ b/src/pathops/SkPathOpsTriangle.cpp
@@ -23,7 +23,7 @@ bool SkDTriangle::contains(const SkDPoint& pt) const {
     double dot12 = v1.dot(v2);
 
 // original code doesn't handle degenerate input; isn't symmetric with inclusion of corner pts;
-// introduces necessary error with divide; doesn't short circuit on early answer
+// introduces error with divide; doesn't short circuit on early answer
 #if 0
 // Compute barycentric coordinates
     double invDenom = 1 / (dot00 * dot11 - dot01 * dot01);