HDFS-16154. TestMiniJournalCluster failing intermittently because of not reseting UserGroupInformation completely (#3270)

Co-authored-by: wangzhaohui8 <wangzhaohui8@jd.com>
Reviewed-by: Viraj Jasani <vjasani@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/qjournal/TestSecureNNWithQJM.java

@@ -154,6 +154,7 @@ public class TestSecureNNWithQJM {
     }
     FileUtil.fullyDelete(baseDir);
     KeyStoreTestUtil.cleanupSSLConfig(keystoresDir, sslConfDir);
+    UserGroupInformation.reset();
   }
 
   @Before