Bug 822364: Skip tests for views that aren't in the urlconf.

- Skips tests that rely on the urls that were removed from the urlconf.
- Fixes an issue with the 404 and 500 pages where they would cause test
  failures when encountered during a test because, during tests, the 
  built-in error views are used, and they don't use RequestContext, 
  which the error templates relied on.