Use per element determination of children vs childNodes, fixes #12488 !strict

git-svn-id: http://svn.dojotoolkit.org/src/dojo/trunk@25510 560b804f-0ae3-0310-86f3-f6aa0a117693

(cherry picked from commit fc262d0d589c490cdd671791f1546a4665ed69c6)