message: Fix memory access violation when finding unresolved flex ops in java api
  It should invoke the node_and_registration method of the corresponding subgraph instead of the interpreter's one when nodes are belong to non-primary subgraph.
diff: @@ -209,7 +209,7 @@ Java_org_tensorflow_lite_NativeInterpreterWrapper_hasUnresolvedFlexOp(
  const auto* subgraph = interpreter->subgraph(static_cast<int>(subgraph_i));
  for (size_t node_i = 0; node_i < subgraph->nodes_size(); ++node_i) {
  const auto& registration =
  - interpreter->node_and_registration(static_cast<int>(node_i))->second;
  + subgraph->node_and_registration(static_cast<int>(node_i))->second;
  if (tflite::IsUnresolvedCustomOp(registration) &&
  tflite::IsFlexOp(registration.custom_name)) {
  return JNI_TRUE;
  