Use Node.contains in IE9/Webkit for isOrHasCHild.  The existing hack was used to work around a Safari 2 bug that is no longer present in Safari 3+.

Review at http://gwt-code-reviews.appspot.com/1725808/

Review by: rdayal@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@11041 8db76d5a-ed1c-0410-87a9-c151d255dfc7