message: Allow single input PACK ops.
diff: @@ -17,10 +17,10 @@ limitations under the License.
  #include <string>
  #include <vector>
  +#include "tensorflow/core/platform/logging.h"
  #include "tensorflow/lite/toco/graph_transformations/graph_transformations.h"
  #include "tensorflow/lite/toco/model.h"
  #include "tensorflow/lite/toco/tooling_util.h"
  -#include "tensorflow/core/platform/logging.h"
  namespace toco {
  @@ -405,8 +405,7 @@ bool HardcodeMinMaxForPack(Model* model, Operator* op) {
  }
  const auto& first_input_minmax = first_input_array.GetMinMax();
  - CHECK_GT(op->inputs.size(), 1);
  - for (int i = 1; i != op->inputs.size(); i++) {
  + for (int i = 1; i < op->inputs.size(); i++) {
  const auto& input_array = model->GetArray(op->inputs[i]);
  if (!input_array.minmax) {
  return false;
  