[SPARK-18606][HISTORYSERVER] remove useless elements while searching

## What changes were proposed in this pull request?

When we search applications in HistoryServer, it will include all contents between <td> tag, which including useless elemtns like "<span title...", "a href" and making results confused.
We should remove those to make it clear.

## How was this patch tested?

manual tests.

Before:
![before](https://cloud.githubusercontent.com/assets/5276001/20662840/28bcc874-b590-11e6-9115-12fb64e49898.jpg)

After:
![after](https://cloud.githubusercontent.com/assets/5276001/20662844/2f717af2-b590-11e6-97dc-a48b08a54247.jpg)

Author: WangTaoTheTonic <wangtao111@huawei.com>

Closes #16031 from WangTaoTheTonic/span.

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

@@ -78,6 +78,12 @@ jQuery.extend( jQuery.fn.dataTableExt.oSort, {
     }
 } );
 
+jQuery.extend( jQuery.fn.dataTableExt.ofnSearch, {
+    "appid-numeric": function ( a ) {
+        return a.replace(/[\r\n]/g, " ").replace(/<.*?>/g, "");
+    }
+} );
+
 $(document).ajaxStop($.unblockUI);
 $(document).ajaxStart(function(){
     $.blockUI({ message: '<h3>Loading history summary...</h3>'});