message: Sort map before serializing it
diff: @@ -3206,8 +3206,11 @@ StatusOr<HloInstruction::FusionKind> StringToFusionKind(
  string FrontendAttributesToString(
  const FrontendAttributes& frontend_attributes) {
  - return absl::StrFormat("{%s}", absl::StrJoin(frontend_attributes.map(), ",",
  - absl::PairFormatter("=")));
  + std::vector<std::pair<string, string>> sorted_attributes(
  + frontend_attributes.map().begin(), frontend_attributes.map().end());
  + std::sort(sorted_attributes.begin(), sorted_attributes.end());
  + return absl::StrFormat(
  + "{%s}", absl::StrJoin(sorted_attributes, ",", absl::PairFormatter("=")));
  }
  string PaddingConfigToString(const PaddingConfig& padding) {
  