[SPARK-21953] Show both memory and disk bytes spilled if either is pr…

…esent

As written now, there must be both memory and disk bytes spilled to show either of them. If there is only one of those types of spill recorded, it will be hidden.

Author: Andrew Ash <andrew@andrewash.com>

Closes apache#19164 from ash211/patch-3.

core/src/main/scala/org/apache/spark/ui/jobs/UIData.scala

@@ -110,7 +110,7 @@ private[spark] object UIData {
     def hasOutput: Boolean = outputBytes > 0
     def hasShuffleRead: Boolean = shuffleReadTotalBytes > 0
     def hasShuffleWrite: Boolean = shuffleWriteBytes > 0
-    def hasBytesSpilled: Boolean = memoryBytesSpilled > 0 && diskBytesSpilled > 0
+    def hasBytesSpilled: Boolean = memoryBytesSpilled > 0 || diskBytesSpilled > 0
   }
 
   /**