Add a getLineNumber() method to AASTToken
Summary: Adds an AASTToken::getLineNumber() method, similar to AASTNode::getLineNumber().
Test Plan: See D13534.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin
Differential Revision: https://secure.phabricator.com/D13889