message: Minor refactor
  Summary: Skip the first interdex group. The diff is noop.
diff: @@ -809,12 +809,13 @@ std::vector<TypeSet> Model::group_per_interdex_set(const TypeSet& types) {
  for (const auto& pair : type_to_usages) {
  auto index = get_interdex_group(pair.second, s_cls_to_interdex_group,
  s_num_interdex_groups);
  - new_groups[index].emplace(pair.first);
  - }
  -
  if (m_spec.merge_per_interdex_set == InterDexGroupingType::NON_HOT_SET) {
  + if (index == 0) {
  // Drop mergeables that are in the hot set.
  - new_groups[0].clear();
  + continue;
  + }
  + }
  + new_groups[index].emplace(pair.first);
  }
  return new_groups;
  