Refactor document views specs

https://www.pivotaltracker.com/story/show/73291456
Summary of changes: https://docs.google.com/document/d/13TNmNkD6__d-7TbnvkNUV8yvCY8bc_SGa6ewxewrciE/edit?usp=sharing
there is a capybara helper method called `save_and_open_page` which does exactly this. Also `open` is a command not present on Linux distributions, many of our contributors use Linux so this would not be a suitable change to introduce.