public void shutdown() throws Exception {
    if (System.getenv(QTEST_LEAVE_FILES) == null) {
      cleanUp();
    }

    miniClusters.shutDown();

    Hive.closeCurrent();
  }
Returns the default UDF names which should not be removed when resetting the test database

@return The list of the UDF names not to remove
itests/util/src/main/java/org/apache/hadoop/hive/ql/QTestUtil.java