Improve PHP compatibility linter

Summary: Ref T8674. Adds to ArcanistPHPCompatibilityXHPASTLinterRule such that an error is raised whenever self or $this is used in an anonymous closure prior to PHP 5.4.

Test Plan: Added test cases.

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: Korvin

Maniphest Tasks: T8674

Differential Revision: https://secure.phabricator.com/D13841