message: Patch RemoveUninstantiables to check for explicitly kept classes
diff: @@ -126,7 +126,7 @@ RemoveUninstantiablesPass::compute_scoped_uninstantiable_types(
  } else if (is_interface(cls) && !is_interface_instantiable(cls)) {
  uninstantiable_types.insert(cls->get_type());
  } else if (is_abstract(cls) && !is_interface(cls) && !cls->is_external() &&
  - !is_native(cls)) {
  + !is_native(cls) && !root(cls)) {
  uninstantiable_types.insert(cls->get_type());
  } else {
  instantiable_classes.insert(cls);
  