@AfterClass
  public static void tearDownAfterClass() throws IOException {
    UTIL.shutdownMiniCluster();
  }
SCP does not support rollback actually, here we just want to simulate that when there is a code
bug, SCP and its sub procedures will not hang there forever, and it will not mess up the
procedure store.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/assignment/TestRollbackSCP.java