Fix the windows test failure by just not testing on windows. :)

Since it's now required in setup.py, we know that the test will run on linux.
On Windows we don't really care if it runs or not -- the fuzz tests are on a
linux machine as far as I'm aware -- and I don't have a windows box to mess with
Visual Studio files in.

Big thanks to zware on #python-dev for walking me through this.

Author: ssbr

Lib/test/test_fuzz.py

@@ -1,5 +1,7 @@
+import test.support
 import unittest
-import _fuzz
+
+_fuzz = test.support.import_module('_fuzz')
 
 class TestFuzz(unittest.TestCase):