Correctly label symbols in n_CLASS_STATIC_ACCESS
Summary: Fixes T6847. These symbols should always be classes, not interfaces.
Test Plan:
test.php
<?php Foo::bar();
> ./scripts/phutil_symbols.php test.php
Reviewers: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Maniphest Tasks: T6847
Differential Revision: https://secure.phabricator.com/D11137