phases: make `allphases` a list on py3 also

Pytype complained that `range` doesn't support slicing, so make this a list like
it was on py2.

Differential Revision: https://phab.mercurial-scm.org/D7468

mercurial/phases.py

@@ -134,7 +134,7 b' HIDEABLE_FLAG = 32 # Phases that are hi'
 public, draft, secret = range(3)
 internal = INTERNAL_FLAG | HIDEABLE_FLAG
 archived = HIDEABLE_FLAG
-allphases = range(internal + 1)
+allphases = list(range(internal + 1))
 trackedphases = allphases[1:]
 # record phase names
 cmdphasenames = [b'public', b'draft', b'secret']  # known to `hg phase` command