modernize reactor::stop()
modernize reactor::stop()

Do not open code new/delete use do_with() instead.

cloudius-systems/seastar,scylladb/seastar,avikivity/seastar,sjperkins/seastar,cloudius-systems/seastar,scylladb/scylla-seastar,avikivity/seastar,kjniemi/seastar,kjniemi/seastar,avikivity/seastar,cloudius-systems/seastar,scylladb/seastar,syuu1228/seastar,dreamsxin/seastar,kjniemi/seastar,dreamsxin/seastar,sjperkins/seastar,scylladb/seastar,scylladb/scylla-seastar,syuu1228/seastar,dreamsxin/seastar,scylladb/scylla-seastar,syuu1228/seastar,sjperkins/seastar