message: Fix tensor lifetime issue in TensorListDeviceCopy
diff: @@ -79,12 +79,10 @@ static Status TensorListDeviceCopy(
  to->max_num_elements = from.max_num_elements;
  to->tensors.reserve(from.tensors.size());
  for (const Tensor& t : from.tensors) {
  - Tensor tmp(t.dtype());
  - // Do not copy uninitialized tensors.
  + to->tensors.emplace_back(t.dtype());
  if (t.dtype() != DT_INVALID) {
  - TF_RETURN_IF_ERROR(copy(t, &tmp));
  + TF_RETURN_IF_ERROR(copy(t, &to->tensors.back()));
  }
  - to->tensors.push_back(tmp);
  }
  return Status::OK();
  }
  