[CELEBORN-1727][FOLLOWUP] Fix CelebornHashCheckDiskSuite flaky test

### What changes were proposed in this pull request?
Fix CelebornHashCheckDiskSuite flaky test .

### Why are the changes needed?
Ditto.

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
UT.

Closes #2937 from onebox-li/fix-flaky-test.

Authored-by: onebox-li <lyh-36@163.com>
Signed-off-by: Shuang <lvshuang.xjs@alibaba-inc.com>
(cherry picked from commit 05ccd96)
Signed-off-by: Shuang <lvshuang.xjs@alibaba-inc.com>

Author: onebox-li

tests/spark-it/src/test/scala/org/apache/celeborn/tests/spark/CelebornHashCheckDiskSuite.scala

@@ -38,9 +38,8 @@ class CelebornHashCheckDiskSuite extends SparkTestBase {
       CelebornConf.APPLICATION_HEARTBEAT_TIMEOUT.key -> "10s")
     val workerConf = Map(
       CelebornConf.WORKER_STORAGE_DIRS.key -> "/tmp:capacity=1000",
-      CelebornConf.WORKER_HEARTBEAT_TIMEOUT.key -> "10s",
       CelebornConf.WORKER_DISK_RESERVE_SIZE.key -> "0G")
-    workers = setupMiniClusterWithRandomPorts(masterConf, workerConf)._2
+    workers = setupMiniClusterWithRandomPorts(masterConf, workerConf, 2)._2
   }
 
   override def beforeEach(): Unit = {