message: Add GUARDED_BY for GlobalJitLevelState.
diff: @@ -22,7 +22,7 @@ namespace xla_config_registry {
  namespace {
  struct GlobalJitLevelState {
  mutex mu;
  - GlobalJitLevelGetterTy getter;
  + GlobalJitLevelGetterTy getter GUARDED_BY(mu);
  };
  GlobalJitLevelState* GetSingletonState() {
  