HDFS-16529. Remove unnecessary setObserverRead in TestConsistentReadsObserver (#4131)

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>
(cherry picked from commit 61bbdfd3a73a18cf05aeb2c40429c34c4b9b0732)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestConsistentReadsObserver.java

@@ -109,8 +109,6 @@ public class TestConsistentReadsObserver {
 
   @Test
   public void testRequeueCall() throws Exception {
-    setObserverRead(true);
-
     // Update the configuration just for the observer, by enabling
     // IPC backoff and using the test scheduler class, which starts to backoff
     // after certain number of calls.