Unreviewed debug build fix for ports enabling the <template> element support.

* html/HTMLTagNames.in: Generate type helpers for the <template> element as they're required
by the assertions in the Element type casts for HTMLTemplateElement.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157033 268f45cc-cd09-0410-ab3c-d52691b4dbfc