[e] (0) The 'reset the insertion mode' algorithm referenced the context element in some cases where there was no context element (e.g. '<html><head></head><template></template>')
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=23664
Affected topics: HTML, HTML Syntax and Parsing

git-svn-id: http://svn.whatwg.org/webapps@8293 340c8d12-0b0e-0410-8428-c7bf67bfef74