Restores our new friend ValueListBox, and muzzles a couple of his
unit tests which seem to fail on FireFox. The widget works
well manually, and M3 needs it.

Review at http://gwt-code-reviews.appspot.com/788801

Review by: amitmanjhi@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@8593 8db76d5a-ed1c-0410-87a9-c151d255dfc7