Simpletests to ensure filter is working properly.

d.o issue: https://www.drupal.org/node/2290277
Umm, this $filtered_html_format is not exactly Drupal's restricted html format. Its a format that we are defining. And since we have not enabled the `filter_html` filter which restricts html tags, this format is essentially full html with the entity_embed filter enables.
I can verify that this works since I've tested in on my local installation.