Ant changes in response to a stable htmlUnit.

Patch by: amitmanjhi
Review by: jlabanca

Review at http://gwt-code-reviews.appspot.com/269801


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7787 8db76d5a-ed1c-0410-87a9-c151d255dfc7