src: remove unused using declarations async_wrap

PR-URL: https://github.com/nodejs/node/pull/18893


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>