This updates the router status test write watch logic to use
an informer, which allows for comparison of the old and new
route objects along with the ability to start the informer
in a separate go routine.

The ability to compare the incoming change allows us to add
filtering to make sure only the updates for our test router are counted.
This greatly simplifies the logic because previously we couldn't filter
out other router updates. As a result, we can remove the logic which
waits for other routers to write status to our test routes.

The informer is now started asynchronously before the routes are
created. This allows us to accurately count all route updates.
Previously, the test routes would be created and then the watch routine
would start immediately after, which leads to the watch missing some
updates.

Add "The HAProxy router converges when multiple routers are
writing conflicting upgrade validation status" test which validates
router converge when writing conflicting status in a scenario that uses
multiple conditions.

Previously, we tested conflicting status fields (hostname), but don't
have a test for conflicting status. This test add logic that exercises
new logic in the router for the Upgrade Validation plugin.