[SPARK-15235][WEBUI] Corresponding row cannot be highlighted even though cursor is on the job on Web UI's timeline

## What changes were proposed in this pull request?

To extract job descriptions and stage name, there are following regular expressions in timeline-view.js

```
var jobIdText = $($(baseElem).find(".application-timeline-content")[0]).text();
var jobId = jobIdText.match("\\(Job (\\d+)\\)")[1];
...
var stageIdText = $($(baseElem).find(".job-timeline-content")[0]).text();
var stageIdAndAttempt = stageIdText.match("\\(Stage (\\d+\\.\\d+)\\)")[1].split(".");
```

But if job descriptions include patterns like "(Job x)" or stage names include patterns like "(Stage x.y)", the regular expressions cannot be match as we expected, ending up with corresponding row cannot be highlighted even though we move the cursor onto the job on Web UI's timeline.

## How was this patch tested?

Manually tested with spark-shell and Web UI.

Author: Kousuke Saruta <[email protected]>

Closes #13016 from sarutak/SPARK-15235.

Author: sarutak

core/src/main/resources/org/apache/spark/ui/static/timeline-view.js

@@ -41,7 +41,7 @@ function drawApplicationTimeline(groupArray, eventObjArray, startTime) {
     $(".item.range.job.application-timeline-object").each(function() {
       var getSelectorForJobEntry = function(baseElem) {
         var jobIdText = $($(baseElem).find(".application-timeline-content")[0]).text();
-        var jobId = jobIdText.match("\\(Job (\\d+)\\)")[1];
+        var jobId = jobIdText.match("\\(Job (\\d+)\\)$")[1];
        return "#job-" + jobId;
       };
 
@@ -113,7 +113,7 @@ function drawJobTimeline(groupArray, eventObjArray, startTime) {
     $(".item.range.stage.job-timeline-object").each(function() {
       var getSelectorForStageEntry = function(baseElem) {
         var stageIdText = $($(baseElem).find(".job-timeline-content")[0]).text();
-        var stageIdAndAttempt = stageIdText.match("\\(Stage (\\d+\\.\\d+)\\)")[1].split(".");
+        var stageIdAndAttempt = stageIdText.match("\\(Stage (\\d+\\.\\d+)\\)$")[1].split(".");
         return "#stage-" + stageIdAndAttempt[0] + "-" + stageIdAndAttempt[1];
       };