Stub out def_parser_test on non-Windows platforms.

See https://github.com/bazelbuild/bazel/issues/4230.

Change-Id: Ia0125d76eb47226ad8e09829e559d636f064b369
RELNOTES: None
diff --git a/third_party/def_parser/empty_test.py b/third_party/def_parser/empty_test.py
new file mode 100644
index 0000000..fe6a40a
--- /dev/null
+++ b/third_party/def_parser/empty_test.py
@@ -0,0 +1,27 @@
+# Copyright 2017 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Empty test for platforms that don't need to run a particular test.
+
+import unittest
+
+
+class EmptyTest(unittest.TestCase):
+
+  def testNothing(self):
+    pass
+
+
+if __name__ == '__main__':
+  unittest.main()