Remove some view_tests in document_controller_test_helpers

We can easily test the fetched documents in assigns, rather than asserting their appearance on the page.  It should be possible to drop the other tests about the pagination links / button and write a unit / helper test for them, but they are implemented directly in a mustache template, so it's not clear what the best way to do it would be.
Tidy view_test in the admin edition attachments macros

Mostly we can check the assigned object and what the state of its edition_attachments is like rather that checking that the fields are on the page.
Merge pull request #580 from alphagov/tidy-some-functional-test-macros

Tidy some functional test macros