[SPARK-23838][WEBUI] Running SQL query is displayed as "completed" in SQL tab

## What changes were proposed in this pull request?

A running SQL query would appear as completed in the Spark UI:
![image1](https://user-images.githubusercontent.com/1097932/38170733-3d7cb00c-35bf-11e8-994c-43f2d4fa285d.png)

We can see the query in "Completed queries", while in in the job page we see it's still running Job 132.
![image2](https://user-images.githubusercontent.com/1097932/38170735-48f2c714-35bf-11e8-8a41-6fae23543c46.png)

After some time in the query still appears in "Completed queries" (while it's still running), but the "Duration" gets increased.
![image3](https://user-images.githubusercontent.com/1097932/38170737-50f87ea4-35bf-11e8-8b60-000f6f918964.png)

To reproduce, we can run a query with multiple jobs. E.g. Run TPCDS q6.

The reason is that updates from executions are written into kvstore periodically, and the job start event may be missed.

## How was this patch tested?
Manually run the job again and check the SQL Tab. The fix is pretty simple.

Author: Gengliang Wang <[email protected]>

Closes apache#20955 from gengliangwang/jobCompleted.

Author: gengliangwang

sql/core/src/main/scala/org/apache/spark/sql/execution/ui/AllExecutionsPage.scala

@@ -39,7 +39,8 @@ private[ui] class AllExecutionsPage(parent: SQLTab) extends WebUIPage("") with L
     val failed = new mutable.ArrayBuffer[SQLExecutionUIData]()
 
     sqlStore.executionsList().foreach { e =>
-      val isRunning = e.jobs.exists { case (_, status) => status == JobExecutionStatus.RUNNING }
+      val isRunning = e.completionTime.isEmpty ||
+        e.jobs.exists { case (_, status) => status == JobExecutionStatus.RUNNING }
       val isFailed = e.jobs.exists { case (_, status) => status == JobExecutionStatus.FAILED }
       if (isRunning) {
         running += e

sql/core/src/main/scala/org/apache/spark/sql/execution/ui/SQLAppStatusListener.scala

@@ -88,7 +88,7 @@ class SQLAppStatusListener(
 
     exec.jobs = exec.jobs + (jobId -> JobExecutionStatus.RUNNING)
     exec.stages ++= event.stageIds.toSet
-    update(exec)
+    update(exec, force = true)
   }
 
   override def onStageSubmitted(event: SparkListenerStageSubmitted): Unit = {
@@ -308,11 +308,13 @@ class SQLAppStatusListener(
       })
   }
 
-  private def update(exec: LiveExecutionData): Unit = {
+  private def update(exec: LiveExecutionData, force: Boolean = false): Unit = {
     val now = System.nanoTime()
     if (exec.endEvents >= exec.jobs.size + 1) {
       exec.write(kvstore, now)
       liveExecutions.remove(exec.executionId)
+    } else if (force) {
+      exec.write(kvstore, now)
     } else if (liveUpdatePeriodNs >= 0) {
       if (now - exec.lastWriteTime > liveUpdatePeriodNs) {
         exec.write(kvstore, now)