Remove all support for cygwin in run-webkit-tests.

third_party/WebKit/Tools/Scripts/webkitpy/common/system/filesystem_unittest.py

 # vim: set fileencoding=utf-8 :
 # Copyright (C) 2010 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #    * Redistributions in binary form must reproduce the above
@@ skipping 219 matching lines @@
 
             # Clean up.
             os.rmdir(sub_path)
 
         self.assertFalse(os.path.exists(base_path))
         self.assertFalse(fs.isdir(base_path))
 
     def test_maybe_make_directory__failure(self):
         # FIXME: os.chmod() doesn't work on Windows to set directories
         # as readonly, so we skip this test for now.
-        if sys.platform in ('win32', 'cygwin'):
+        if sys.platform == 'win32':
             return
 
         fs = FileSystem()
         with fs.mkdtemp(prefix='filesystem_unittest_') as d:
             # Remove write permissions on the parent directory.
             os.chmod(d, stat.S_IRUSR)
 
             # Now try to create a sub directory - should fail.
             sub_dir = fs.join(d, 'subdir')
             self.assertRaises(OSError, fs.maybe_make_directory, sub_dir)
@@ skipping 68 matching lines @@
         fs = FileSystem()
         self.assertTrue(fs.remove('filename', remove_with_exception))
         self.assertEqual(-1, RealFileSystemTest._remove_failures)
 
     def test_sep(self):
         fs = FileSystem()
 
         self.assertEqual(fs.sep, os.sep)
         self.assertEqual(fs.join('foo', 'bar'),
                          os.path.join('foo', 'bar'))