message: Add shape check to TFRecordDataset
  The inputs of TFRecordDataset have the requirements for shapes.
  However, the check was not done in the shape function. This fix
  adds shape checks whenever possible.
diff: @@ -417,7 +417,12 @@ REGISTER_OP("TFRecordDataset")
  .Output("handle: variant")
  .SetIsStateful() // TODO(b/65524810): Source dataset ops must be marked
  // stateful to inhibit constant folding.
  - .SetShapeFn(shape_inference::ScalarShape);
  + .SetShapeFn([](shape_inference::InferenceContext* c) {
  + shape_inference::ShapeHandle unused;
  + // `filenames` must be a scalar or a vector.
  + TF_RETURN_IF_ERROR(c->WithRankAtMost(c->input(0), 1, &unused));
  + return shape_inference::ScalarShape(c);
  + });
  REGISTER_OP("Iterator")
  .Output("handle: resource")
  