[SPARK-21286][TEST] Modified StorageTabSuite unit test

## What changes were proposed in this pull request?
The old unit test not effect

## How was this patch tested?
unit test

Author: he.qiao <he.qiao17@zte.com.cn>

Closes #18511 from Geek-He/dev_0703.

core/src/test/scala/org/apache/spark/ui/storage/StorageTabSuite.scala

@@ -74,7 +74,7 @@ class StorageTabSuite extends SparkFunSuite with BeforeAndAfter {
     // Submitting RDDInfos with duplicate IDs does nothing
     val rddInfo0Cached = new RDDInfo(0, "freedom", 100, StorageLevel.MEMORY_ONLY, Seq(10))
     rddInfo0Cached.numCachedPartitions = 1
-    val stageInfo0Cached = new StageInfo(0, 0, "0", 100, Seq(rddInfo0), Seq.empty, "details")
+    val stageInfo0Cached = new StageInfo(0, 0, "0", 100, Seq(rddInfo0Cached), Seq.empty, "details")
     bus.postToAll(SparkListenerStageSubmitted(stageInfo0Cached))
     assert(storageListener._rddInfoMap.size === 4)
     assert(storageListener.rddInfoList.size === 2)