[Backport IE fixes to 1.7] allow for IE9+'s async focus in Form test, refs #11800

git-svn-id: http://svn.dojotoolkit.org/src/dijit/trunk@31106 560b804f-0ae3-0310-86f3-f6aa0a117693
(cherry picked from commit a63501c383e1fe018aeec952dc490719fb644df5)
(cherry picked from commit 919a3428177c010c010f4bbcc2f897ee2c4b7df7)