[Backport IE11 fixes to 1.7] fix spurious Dialog test failures on IE10 due to async focus(), refs #16926

cherry-picked from: https://github.com/dojo/dijit/commit/db846a232891b365c26d92698a6798bc6f0c59bd

git-svn-id: http://svn.dojotoolkit.org/src/dijit/trunk@31076 560b804f-0ae3-0310-86f3-f6aa0a117693

Conflicts:
	tests/Dialog.html