Cancelling the opening unpaid order ran the expiry sweep only implicitly, so a
group whose lifetime had already ended was relabelled cancelled instead of
expired. Both conditions hold in that case; sweep first so the lifetime ending
wins. The behaviour was invisible to shoppers (neither state is joinable) but it
matters to a future refund flow reading expired paid groups.
Add an integration test that reproduces the precedence.
james
d7fddf53ab