IE gives exceptions in console if you try to delete an expando property that doesn't exist, refs #16576 !strict.
Don't assume that the focus manager is loaded or dojo.subscribe is defined in the iframe.   For AMD tests they may not be.   Plus fixing a few references to the dojo global.  Refs #14279 !strict.
Add missing  dependency, refs #14279 !strict.
Access dijit/tests/helpers methods through AMD, refs #14279.