[SPARK-26196][SPARK-26281][WEBUI] Total tasks title in the stage page…

… is incorrect when there are failed or killed tasks and update duration metrics

## What changes were proposed in this pull request?
This PR fixes 3 issues
1) Total tasks message in the tasks table is incorrect, when there are failed or killed tasks
2) Sorting of the "Duration" column is not correct
3) Duration in the aggregated tasks summary table and the tasks table and not matching.

Total tasks  = numCompleteTasks +  numActiveTasks + numKilledTasks + numFailedTasks;

Corrected the duration metrics in the tasks table as executorRunTime based on the PR #23081

## How was this patch tested?
test step:
1)
```
bin/spark-shell
scala > sc.parallelize(1 to 100, 10).map{ x => throw new RuntimeException("Bad executor")}.collect()
```
![screenshot from 2018-11-28 07-26-00](https://user-images.githubusercontent.com/23054875/49123523-e2691880-f2de-11e8-9c16-60d1865e6e77.png)

After patch:
![screenshot from 2018-11-28 07-24-31](https://user-images.githubusercontent.com/23054875/49123525-e432dc00-f2de-11e8-89ca-4a53e19c9c18.png)

2)  Duration metrics:
Before patch:
![screenshot from 2018-12-06 03-25-14](https://user-images.githubusercontent.com/23054875/49546591-9e8d9900-f906-11e8-8a0b-157742c47655.png)

After patch:
![screenshot from 2018-12-06 03-23-14](https://user-images.githubusercontent.com/23054875/49546589-9cc3d580-f906-11e8-827f-52ef8ffdeaec.png)

Closes #23160 from shahidki31/totalTasks.

Authored-by: Shahid <shahidki31@gmail.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>

core/src/main/resources/org/apache/spark/ui/static/stagepage.js

@@ -616,7 +616,8 @@ $(document).ready(function () {
                 $("#accumulator-table").DataTable(accumulatorConf);
 
                 // building tasks table that uses server side functionality
-                var totalTasksToShow = responseBody.numCompleteTasks + responseBody.numActiveTasks;
+                var totalTasksToShow = responseBody.numCompleteTasks + responseBody.numActiveTasks +
+                    responseBody.numKilledTasks + responseBody.numFailedTasks;
                 var taskTable = "#active-tasks-table";
                 var taskConf = {
                     "serverSide": true,
@@ -667,8 +668,8 @@ $(document).ready(function () {
                         {data : "launchTime", name: "Launch Time", render: formatDate},
                         {
                             data : function (row, type) {
-                                if (row.duration) {
-                                    return type === 'display' ? formatDuration(row.duration) : row.duration;
+                                if (row.taskMetrics && row.taskMetrics.executorRunTime) {
+                                    return type === 'display' ? formatDuration(row.taskMetrics.executorRunTime) : row.taskMetrics.executorRunTime;
                                 } else {
                                     return "";
                                 }
@@ -927,7 +928,7 @@ $(document).ready(function () {
 
                 // title number and toggle list
                 $("#summaryMetricsTitle").html("Summary Metrics for " + "<a href='#tasksTitle'>" + responseBody.numCompleteTasks + " Completed Tasks" + "</a>");
-                $("#tasksTitle").html("Task (" + totalTasksToShow + ")");
+                $("#tasksTitle").html("Tasks (" + totalTasksToShow + ")");
 
                 // hide or show the accumulate update table
                 if (accumulatorTable.length == 0) {

core/src/main/scala/org/apache/spark/status/api/v1/StagesResource.scala

@@ -210,7 +210,6 @@ private[v1] class StagesResource extends BaseAppResource {
       (containsValue(f.taskId) || containsValue(f.index) || containsValue(f.attempt)
         || containsValue(f.launchTime)
         || containsValue(f.resultFetchStart.getOrElse(defaultOptionString))
-        || containsValue(f.duration.getOrElse(defaultOptionString))
         || containsValue(f.executorId) || containsValue(f.host) || containsValue(f.status)
         || containsValue(f.taskLocality) || containsValue(f.speculative)
         || containsValue(f.errorMessage.getOrElse(defaultOptionString))