Make parallel unit testing work on windows

gyp/pathops_unittest.gyp

 # GYP file to build unit tests.
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
     {
       'target_name': 'pathops_unittest',
       'type': 'executable',
       'include_dirs' : [
@@ skipping 88 matching lines @@
         '../tests/PathOpsQuadLineIntersectionThreadedTest.cpp',
         '../tests/PathOpsQuadParameterizationTest.cpp',
         '../tests/PathOpsQuadReduceOrderTest.cpp',
         '../tests/PathOpsSimplifyDegenerateThreadedTest.cpp',
         '../tests/PathOpsSimplifyQuadralateralsThreadedTest.cpp',
         '../tests/PathOpsSimplifyQuadThreadedTest.cpp',
         '../tests/PathOpsSimplifyRectThreadedTest.cpp',
         '../tests/PathOpsSimplifyTest.cpp',
         '../tests/PathOpsSimplifyTrianglesThreadedTest.cpp',
         '../tests/PathOpsTestCommon.cpp',
+        '../tests/PathOpsThreadedCommon.cpp',
         '../tests/PathOpsCubicIntersectionTestData.h',
         '../tests/PathOpsExtendedTest.h',
         '../tests/PathOpsQuadIntersectionTestData.h',
         '../tests/PathOpsTestCommon.h',
+        '../tests/PathOpsThreadedCommon.h',
         '../tests/Test.cpp',
         '../tests/skia_test.cpp',
         '../tests/Test.h',
       ],
       'dependencies': [
         'skia_base_libs.gyp:skia_base_libs',
         'effects.gyp:effects',
         'images.gyp:images',
         'utils.gyp:utils',
       ],
       'conditions': [
         [ 'skia_gpu == 1', {
           'include_dirs': [
             '../src/gpu',
           ],
         }],
       ],
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: