message: Fix test to handle different int size on windows
  The default numpy type in windows ends up being int32 vs int64.
diff: @@ -158,7 +158,7 @@ class CastOpTest(test.TestCase):
  self.evaluate(math_ops.cast(x, dtype))
  def testNotImplemented(self):
  - self._OpError(np.arange(0, 10), dtypes.string, "Cast.*int64.*string.*")
  + self._OpError(np.arange(0, 10), dtypes.string, "Cast.*int.*string.*")
  def testCastToTypeOfVariable(self):
  with self.cached_session():
  