harden and speed up path op unit tests

tests/PathOpsDCubicTest.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 "PathOpsTestCommon.h"
 #include "SkPathOpsCubic.h"
 #include "Test.h"
 
 static const SkDCubic tests[] = {
     {{{2, 0}, {3, 1}, {2, 2}, {1, 1}}},
     {{{3, 1}, {2, 2}, {1, 1}, {2, 0}}},
     {{{3, 0}, {2, 1}, {3, 2}, {1, 1}}},
 };
 
 static const size_t tests_count = SK_ARRAY_COUNT(tests);
 
 static void PathOpsDCubicTest(skiatest::Reporter* reporter) {
     for (size_t index = 0; index < tests_count; ++index) {
         const SkDCubic& cubic = tests[index];
+        SkASSERT(ValidCubic(cubic));
         bool result = cubic.clockwise();
         if (!result) {
             SkDebugf("%s [%d] expected clockwise\n", __FUNCTION__, index);
             REPORTER_ASSERT(reporter, 0);
         }
     }
 }
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS_SHORT(PathOpsDCubicTest)