reactor: use no_sanitize("undefined")
reactor: use no_sanitize("undefined")

[[gnu::no_sanitize_undefined]] is not supported by clang.

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