Path getClusterTestDir() {
    if (clusterTestDir == null) {
      setupClusterTestDir();
    }
    return new Path(clusterTestDir.getAbsolutePath());
  }
Returns Where the cluster will write data on the local subsystem. Creates it if it does not
exist already. A subdir of {@code HBaseCommonTestingUtility#getBaseTestDir()}
hbase-zookeeper/src/test/java/org/apache/hadoop/hbase/HBaseZKTestingUtil.java