Identify published commits in working copies by using remote configuration

Summary:
Ref T13546. When running "arc branches", we want to show all unpublished commits. This is often a different set of commits than "commits not present in any remote".

Attempt to identify published commits by using the permanent ref rules in Phabricator.

Test Plan: Ran "arc look published", saw sensible published commits in Git.

Maniphest Tasks: T13546

Differential Revision: https://secure.phabricator.com/D21378