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
pager.pager=p0 # $TESTTMP/sysrc:4
ui.editor=e1 # $TESTTMP/userrc:2
pager.pager=p2 # $PAGER
ui.editor=e1 # $TESTTMP/userrc:2