fix bugs found by computing flat clips in 800K skps

tests/PathOpsSimplifyTest.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "PathOpsExtendedTest.h"
 
 #define TEST(name) { name, #name }
 
@@ skipping 4635 matching lines @@
     path.quadTo(0, 0, 2, 0);
     path.lineTo(1, 1);
     path.close();
     path.moveTo(0, 0);
     path.lineTo(0, 0);
     path.quadTo(1, 0, 2, 2);
     path.close();
     testSimplify(reporter, path, filename);
 }
 
-static void (*firstTest)(skiatest::Reporter* , const char* filename) = testQuadratic56;
+static void testQuadralateral10(skiatest::Reporter* reporter, const char* filename) {
+    SkPath path;
+    path.setFillType(SkPath::kWinding_FillType);
+    path.moveTo(0, 0);
+    path.lineTo(0, 0);
+    path.lineTo(0, 0);
+    path.lineTo(2, 2);
+    path.close();
+    path.moveTo(1, 0);
+    path.lineTo(1, 1);
+    path.lineTo(2, 2);
+    path.lineTo(1, 3);
+    path.close();
+    testSimplify(reporter, path, filename);
+}
+
+static void (*firstTest)(skiatest::Reporter* , const char* filename) = 0;
 
 static TestDesc tests[] = {
+    TEST(testQuadralateral10),
     TEST(testQuads61),
     TEST(testQuads60),
     TEST(testQuads59),
     TEST(testQuads58),
     TEST(testQuads57),
     TEST(testQuads56),
     TEST(testQuads54),
     TEST(testQuads53),
     TEST(testQuads52),
     TEST(testQuads51),
@@ skipping 418 matching lines @@
 
 DEF_TEST(PathOpsSimplify, reporter) {
     if (runSubTests && runSubTestsFirst) {
         RunTestSet(reporter, subTests, subTestCount, firstSubTest, stopTest, runReverse);
     }
     RunTestSet(reporter, tests, testCount, firstTest, stopTest, runReverse);
     if (runSubTests && !runSubTestsFirst) {
         RunTestSet(reporter, subTests, subTestCount, firstSubTest, stopTest, runReverse);
     }
 }