deal more consistently with unsortable edges

tests/PathOpsSimplifyTest.cpp

Index: tests/PathOpsSimplifyTest.cpp
diff --git a/tests/PathOpsSimplifyTest.cpp b/tests/PathOpsSimplifyTest.cpp
index de08bd81d946123cd49834b8bf177258d07ce2a7..8da3cab389a1fa7cff2e3c673d64393ec32ba660 100644
--- a/tests/PathOpsSimplifyTest.cpp
+++ b/tests/PathOpsSimplifyTest.cpp
@@ -4752,11 +4752,19 @@ static void testTriangle2(skiatest::Reporter* reporter,const char* filename) {
     testSimplify(reporter, path, filename);
 }
 
+static void testArc(skiatest::Reporter* reporter,const char* filename) {
+    SkRect r = SkRect::MakeWH(150, 100);
+    SkPath path;
+    path.arcTo(r, 0, 0.0025f, false);
+    testSimplify(reporter, path, filename);
+}
+
 static void (*skipTest)(skiatest::Reporter* , const char* filename) = 0;
 static void (*firstTest)(skiatest::Reporter* , const char* filename) = 0;
 static void (*stopTest)(skiatest::Reporter* , const char* filename) = 0;
 
 static TestDesc tests[] = {
+    TEST(testArc),
     TEST(testTriangle2),
     TEST(testTriangle1),
     TEST(testQuads64),