The Dashboard makes every Behat test very very slow for @javascript tests

1. When you log in in Moodle, you are redirected to your Dashboard.
2. Since every Behat test starts with all the caches empty, it takes >10s to render the dashboard. (Acutally, in my last Behat test run which had 4 scenarios, the times for the login steps were 34s, 17s, 18s and 22s most of that caused by the dashboard.)
3. What I am testing has nothing to do with the dashboard anyway.

More generally, we have this history that every Behat scenario starts be testing some irrelevant navigation.

My suggestion would be that we should make a single step:

When I am on "C100" "core_course" "homepage" logged in as "admin"

To support this every component could optionally implement a get_url($type, $descriptor) method in their behat class. E.g. the above would call behat_course::get_url with "homepage" and "C100".

I am assuming there is some way to get $SESSION->wantsurl set to make it work.