log: predict logger::is_enabled() as false
log: predict logger::is_enabled() as false

This will move trace/debug-level logging out of the way. It's true that
that info+ levels will be mispredicted, but logging is so slow anyway
that we don't care.
Message-Id: <69edf871dd0bdf45146f993bca1e7f30cdad5844@scylladb.com>

avikivity/seastar,scylladb/seastar,scylladb/seastar,avikivity/seastar,syuu1228/seastar,dreamsxin/seastar,cloudius-systems/seastar,cloudius-systems/seastar,scylladb/seastar,dreamsxin/seastar,syuu1228/seastar,cloudius-systems/seastar,dreamsxin/seastar,syuu1228/seastar,avikivity/seastar