fix unit test (#12817) (#12932)

(cherry picked from commit 10fc755)

Signed-off-by: kkewwei <kkewwei@163.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

server/src/test/java/org/opensearch/cluster/service/TaskBatcherTests.java

@@ -218,7 +218,8 @@ public void testTasksAreExecutedInOrder() throws BrokenBarrierException, Interru
             executors[i] = new TaskExecutor();
         }
 
-        int tasksSubmittedPerThread = randomIntBetween(2, 1024);
+        // it will create at most 8192 threads, which will cause native memory oom. so we limit the number of created threads.
+        int tasksSubmittedPerThread = randomIntBetween(2, 128);
 
         CopyOnWriteArrayList<Tuple<String, Throwable>> failures = new CopyOnWriteArrayList<>();
         CountDownLatch updateLatch = new CountDownLatch(numberOfThreads * tasksSubmittedPerThread);
@@ -286,7 +287,7 @@ public void testNoTasksAreDroppedInParallelSubmission() throws BrokenBarrierExce
             executors[i] = new TaskExecutor();
         }
 
-        int tasksSubmittedPerThread = randomIntBetween(2, 1024);
+        int tasksSubmittedPerThread = randomIntBetween(2, 128);
 
         CopyOnWriteArrayList<Tuple<String, Throwable>> failures = new CopyOnWriteArrayList<>();
         CountDownLatch updateLatch = new CountDownLatch(numberOfThreads * tasksSubmittedPerThread);