@After
  public void tearDown() throws IOException {
    region = null;
    TRACKER = null;
    UTIL.deleteTable(NAME);
  }
Confirm that the function of CompactionLifeCycleTracker is OK as we do not use it in our own
code.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestCompactionLifeCycleTracker.java