message: Fix Windows cwise_ops_test.py bfloat16 failure.
  Test was broken by
diff: @@ -840,14 +840,16 @@ class MathOpsOverloadTest(test.TestCase):
  return self.evaluate(z)
  def _compareBinary(self, x, y, dtype, np_func, tf_func):
  - np_ans = np_func(x, y).astype(dtype.as_numpy_dtype)
  - if dtype == dtypes_lib.bfloat16:
  - # assertAllClose does not properly handle bfloat16 values
  - np_ans = np_ans.astype(np.float32)
  + # astype and assertAllClose do not properly handle bfloat16 values
  + np_ans = np_func(x, y).astype(np.float32 if dtype == dtypes_lib.bfloat16
  + else dtype.as_numpy_dtype)
  + rtol = 1e-2 if dtype == dtypes_lib.bfloat16 else 1e-6
  self.assertAllClose(np_ans,
  - self._computeTensorAndLiteral(x, y, dtype, tf_func))
  + self._computeTensorAndLiteral(x, y, dtype, tf_func),
  + rtol=rtol)
  self.assertAllClose(np_ans,
  - self._computeLiteralAndTensor(x, y, dtype, tf_func))
  + self._computeLiteralAndTensor(x, y, dtype, tf_func),
  + rtol=rtol)
  def _compareUnary(self, x, dtype, np_func, tf_func):
  np_ans = np_func(x).astype(dtype.as_numpy_dtype)
  