Put touch click normalization in dojo/touch, rather than in dijit/a11yclick and various mobile modules.   Unlike the old dijit/a11yclick code, the new code works by squelching the real click event, and instead always generating a synthetic click event.   Limited to nodes that have a dojoClick property set, or an ancestor with the dojoClick property set.  Patch from Eric Durocher (IBM, CCLA), fixes #15878 !strict.

Some dijit widgets like dijit/Tree and dijit/!TitlePane are currently manually listening for click events and keyboard events; they need to be updated to set the dojoClick property on their nodes instead.