message: Remove Placeholder op verification in GraphDef import
  This applies the TODO to remove this check when the ops are directly created in the TensorFlow dialect.
diff: @@ -847,11 +847,6 @@ Status Importer::ConvertFunctionArgAndRets(
  builder_->setInsertionPoint(inst);
  auto* input = builder_->createOperation(state);
  arg_def = input->getResult(arg_nodes[i].index);
  - // Verify on the equivalent TF op would have failed, but catching this
  - // earlier for now as this exposed a bug. TODO(jpienaar): remove post
  - // dialect refactoring.
  - DCHECK(input->getResult(0)->getType() == input->getOperand(0)->getType())
  - << "invalid placeholder_input constructed";
  for (auto index = 0; index < inst->getNumResults(); index++) {
  inst->getResult(index)->replaceAllUsesWith(arg_def);
  