message: [TF:XLA] Small improvement in HloModuleGroupUtil::CycleToString.
diff: @@ -232,12 +232,7 @@ string HloModuleGroupUtil::CycleToString(HloInstruction* init_instruction) {
  };
  helper(init_instruction);
  - std::vector<string> pieces;
  - pieces.reserve(names.size());
  - for (auto name : names) {
  - pieces.push_back(name);
  - }
  - return absl::StrJoin(pieces, " --> ");
  + return absl::StrJoin(names, " --> ");
  }
  Status HloModuleGroupUtil::VisitTopologicalOrder(
  