Fixes a regression for inserting the Jazzcat Loader, and adds a regression test.
Renaming insertJazzcatLoader to htmlWithJazzcatLoader
Changing fixture variable name
Moving comment
Cleanup Jazzcat fixes.

- Rename `htmlWithJazzcatLoader` for clarity.
- Fix incorrect comments.
- Cleanup tests.
Ensure the regression is completely tested.
Merge pull request #153 from mobify/v2.0-jazzcat-loader-regression

Jazzcat loader regression