message: Remove outdated TODOs.
  Dynamic tensor support is already implemented in while.cc
diff: @@ -155,7 +155,6 @@ TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
  TF_LITE_ENSURE_OK(context, cond_subgraph->AllocateTensors());
  TfLiteTensor* cond_output =
  cond_subgraph->tensor(cond_subgraph->outputs()[0]);
  - // TODO(ycling): Handle the case the cond subgraph has dynamic tensor outputs.
  // This should rarely happens. In most cases the output is static with shape
  // [1]. However theoretically intermediate tensors in the cond subgraph
  // can be dynamic.
  @@ -181,7 +180,6 @@ TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
  body_subgraph->tensor(body_subgraph->outputs()[i]);
  TF_LITE_ENSURE_TYPES_EQ(context, body_input->type, body_output->type);
  - // TODO(ycling): Support dynamic sized body subgraph.
  TF_LITE_ENSURE(context, !IsDynamicTensor(body_output));
  if (!TfLiteIntArrayEqual(body_input->dims, body_output->dims)) {
  // If the output shape of the body subgraph is static w.r.t. a fixed
  