Add a test to verify that all routing maps are plausibly valid, and remove some dead routes

Summary:
Previously, see D20999. See also https://discourse.phabricator-community.org/t/the-phutil-library-phutil-has-not-been-loaded/3543/.

There are a couple of dead "Config" routes after recent changes. Add test coverage to make sure routes all point somewhere valid, then remove all the dead routes that turned up.

Test Plan: Ran tests, saw failures. Removed dead routes, got clean tests.

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Differential Revision: https://secure.phabricator.com/D21000