message: Make array_ops_test.py work with the C API enabled.
  I only enabled the test class that other testing identified needed changes.
diff: @@ -975,6 +975,7 @@ class ShapeSizeRankTest(test_util.TensorFlowTestCase):
  self.assertEqual(2, array_ops.rank(sp).eval())
  +@test_util.with_c_api
  class SequenceMaskTest(test_util.TensorFlowTestCase):
  def testExceptions(self):
  @@ -993,6 +994,9 @@ class SequenceMaskTest(test_util.TensorFlowTestCase):
  # test dtype and default maxlen:
  res = array_ops.sequence_mask(
  constant_op.constant([0, 1, 4]), dtype=dtypes.float32)
  + if ops._USE_C_API:
  + self.assertAllEqual(res.get_shape().as_list(), [3, 4])
  + else:
  self.assertAllEqual(res.get_shape().as_list(), [3, None])
  self.assertAllEqual(res.eval(), [[0.0, 0.0, 0.0,
  0.0], [1.0, 0.0, 0.0, 0.0],
  @@ -1009,6 +1013,9 @@ class SequenceMaskTest(test_util.TensorFlowTestCase):
  # test dtype and default maxlen:
  res = array_ops.sequence_mask(
  constant_op.constant([[0, 1, 4], [1, 2, 3]]), dtype=dtypes.float32)
  + if ops._USE_C_API:
  + self.assertAllEqual(res.get_shape().as_list(), [2, 3, 4])
  + else:
  self.assertAllEqual(res.get_shape().as_list(), [2, 3, None])
  self.assertAllEqual(res.eval(), [[[0.0, 0.0, 0.0, 0.0],
  [1.0, 0.0, 0.0, 0.0],
  