revset: use phasecache.getrevset to calculate public() Other revsets like secret(), draft(), _nonpublic() are using phasescache.getrevset already. The latter is more efficient after D1606. So let's migrate the public() revset function too. Tested using: $ hg debugshell --hidden --cwd hg-committed` In [1]: %timeit len(repo.revs('public()')) * Before D1606: 10 loops, best of 3: 22.5 ms per loop * Before this change, after D1606: 10 loops, best of 3: 28.6 ms per loop * After this change: 10 loops, best of 3: 20.2 ms per loop Therefore `public()` revset becomes even slightly faster after the data structure change by D1606. A similar performance win could also be observed on a large repo. A side effect is `phasecache.getrevset` needs to take a `subset` parameter. That was added with a default value so it won't cause BC issues. Differential Revision: https://phab.mercurial-scm.org/D1620