Remove deprecated ComprehensiveLintEngine class

Summary: Ref T5655. This class was deprecated in D11673.

Test Plan: Wait a few months.

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T5655

Differential Revision: https://secure.phabricator.com/D11740