Remove the ArcanistArcanistLinterTestCase

Summary: I don't think that this provides too much value. I think that we should rework this to be inferred from the .arcconfig file perhaps?

Test Plan: arc unit

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11662