[SPARK-29053][WEBUI] Sort does not work on some columns

Setting custom sort key for duration and execution time column.

Sorting on duration and execution time columns consider time as a string after converting into readable form which is the reason for wrong sort results as mentioned in [SPARK-29053](https://issues.apache.org/jira/browse/SPARK-29053).

No

Test manually. Screenshots are attached.

After patch:
**Duration**
![Duration](https://user-images.githubusercontent.com/40591404/65339861-93cc9800-dbea-11e9-95e6-63b107a5a372.png)
**Execution time**
![Execution Time](https://user-images.githubusercontent.com/40591404/65339870-97601f00-dbea-11e9-9d1d-690c59bc1bde.png)

Closes #25855 from amanomer/SPARK29053.

Authored-by: aman_omer <amanomer1996@gmail.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>

Author: amanomer

sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/ui/ThriftServerPage.scala

@@ -90,7 +90,8 @@ private[ui] class ThriftServerPage(parent: ThriftServerTab) extends WebUIPage(""
           <td>{info.groupId}</td>
           <td>{formatDate(info.startTimestamp)}</td>
           <td>{if (info.finishTimestamp > 0) formatDate(info.finishTimestamp)}</td>
-          <td>{formatDurationOption(Some(info.totalTime))}</td>
+          <td sorttable_customkey={info.totalTime.toString}>
+            {formatDurationOption(Some(info.totalTime))}</td>
           <td>{info.statement}</td>
           <td>{info.state}</td>
           {errorMessageCell(detail)}
@@ -155,7 +156,8 @@ private[ui] class ThriftServerPage(parent: ThriftServerTab) extends WebUIPage(""
           <td> <a href={sessionLink}> {session.sessionId} </a> </td>
           <td> {formatDate(session.startTimestamp)} </td>
           <td> {if (session.finishTimestamp > 0) formatDate(session.finishTimestamp)} </td>
-          <td> {formatDurationOption(Some(session.totalTime))} </td>
+          <td sorttable_customkey={session.totalTime.toString}>
+            {formatDurationOption(Some(session.totalTime))} </td>
           <td> {session.totalExecution.toString} </td>
         </tr>
       }