DoYouEvenBench: Make it work on Internet Explorer 11 Release Preview

DoYouEvenBench: Make it work on Internet Explorer 11 Release Preview
https://bugs.webkit.org/show_bug.cgi?id=122406

Reviewed by Darin Adler.

On Internet Explorer 11, $(elem).closest('li').data('id') fails to find the containig li of elem once
the first item is marked complete or deleted until we get back to the event loop in the jQuery/TodoMVC.
Worked around this limitation by overriding app.getTodo to use each item's id computed in advance.

Also use $.text instead of execCommand('InsertText') in FlightJS/MailClient since Internet Explorer
doesn't support execCommand('InsertText'). Also select the recipient to avoid exceptions.

* DoYouEvenBench/benchmark.html:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@157009 268f45cc-cd09-0410-ab3c-d52691b4dbfc