fix blank.

Author: hfutatzhanghb

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/async/TestDisableNameservicesExample.java

@@ -76,7 +76,7 @@ public class TestDisableNameservicesExample {
   @Nested
   @ExtendWith(RouterServerHelper.class)
   class TestWithAsyncRouterRpc {
-    
+  
     @ParameterizedTest
     @ValueSource(strings = {"ASYNC"})
     public void testMetricsAsync(String rpcMode) throws Exception {