Only test symbols from the current library

Summary: Limit the acceptance testing surrounding symbols to only consider symbols from the current library. See D11052#107199.

Test Plan: Increased the method visibility of a class in rARC and ran arc lint -- src/ in rP.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11417