Write tests for dom parser against special tags such as <tr> and </td>.

[treshugart]

Currently if you set innerHTML to a <table> and you specify special table elements, they'll be wrapped in a <div> due to https://github.com/skatejs/named-slots/pull/46 which is a necessary fix for <style> tags.

We'll probably end up needing to test the incoming HTML string to see if it starts with a special tag, and if so, wrap it accordingly.

Note: this is only necessary for WebKit because of the property accessor issue.