message: make calling NNAPI work again
  (this a copy of which apparently got lost in the one of the merges)
diff: @@ -303,7 +303,6 @@ TfLiteStatus Interpreter::Invoke() {
  TfLiteStatus status = kTfLiteOk;
  if (nnapi_delegate_) {
  - TF_LITE_ENSURE_STATUS(PrepareOpsAndTensors());
  if (next_execution_plan_index_to_prepare_ == execution_plan_.size()) {
  TF_LITE_ENSURE_OK(&context_, nnapi_delegate_->Invoke(this));
  return kTfLiteOk;
  