Add failing test for auto-update bug
Add failing test for auto-update bug

Because search calls are asyncronous, it is possible for the results on a page to be in-consistent with the search form. This happens as follows:

1. Checkbox1 is checked triggering a search
2. An asynchronous call to the server (via cache etc) is made (call1)
3. Checkbox1 is unchecked triggering another search
4. Another async call to server is made (call2)
5. Call2 returns before call1
6. Search results for call2 are displayed
7. Call1 returns
8. Search results for call1 are displayed
9. The search results are now out of step with the checkboxes :(

This test requires that a state is passed in with the response when calling displayResults() and if the state matches the current (i.e. most up to date state) then the search results should be updated, else they should be ignored.

alphagov/finder-frontend,alphagov/finder-frontend,alphagov/finder-frontend,alphagov/finder-frontend