Fixes #16194.  Don't call validate() until _created==true.
This also restores all the tests erroneously removed in 948cda25a51f8f065a99c1d018beb6889cb3a380.

git-svn-id: http://svn.dojotoolkit.org/src/dijit/trunk@29878 560b804f-0ae3-0310-86f3-f6aa0a117693
(cherry picked from commit 73f44da76b7b09cd80e3785e193cccd798158c92)