in module managed-ledger, the testcase startup zookeeper server, af…

…ter startup zookeeper server, we will use `ClientBase.waitForServerUp(getZooKeeperConnectString(), ClientBase.CONNECTION_TIMEOUT)` to wait for zookeeper server startup success, but if zookeeper do not enable `zookeeper.4lw.commands.whitelist`, the client can not use (apache#6727)

   In module `managed-ledger`,  the testcase startup zookeeper server, after startup zookeeper server, we will use `ClientBase.waitForServerUp(getZooKeeperConnectString(), ClientBase.CONNECTION_TIMEOUT)` to wait for zookeeper server startup success, but if zookeeper do not enable `zookeeper.4lw.commands.whitelist`, the client can not use
`echo stat  |  nc zookeeper_ip  zk_port` to detect zookeeper server startup success or not

managed-ledger/src/test/java/org/apache/bookkeeper/test/BookKeeperClusterTestCase.java

@@ -93,6 +93,8 @@ public BookKeeperClusterTestCase(int numBookies) {
 
     @BeforeMethod
     public void setUp() throws Exception {
+        // enable zookeeper `zookeeper.4lw.commands.whitelist`
+        System.setProperty("zookeeper.4lw.commands.whitelist", "*");
         executor = Executors.newCachedThreadPool();
         InMemoryMetaStore.reset();
         setMetastoreImplClass(baseConf);