void undoBatchAction(BalancerClusterState cluster, MoveBatchAction batchAction) {
    for (int i = batchAction.getMoveActions().size() - 1; i >= 0; i--) {
      MoveRegionAction action = batchAction.getMoveActions().get(i);
      cluster.doAction(action.undoAction());
    }
  }
Generates a balancing action to appease the conditional.
@param cluster    Current state of the cluster.
@param isWeighing Flag indicating if the generator is being used for weighing.
@return A BalanceAction, or NULL_ACTION if no action is needed.
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/RegionPlanConditionalCandidateGenerator.java