async_hooks: skip runtime checks when disabled

PR-URL: https://github.com/nodejs/node/pull/15454
Ref: https://github.com/nodejs/node/pull/14387
Ref: https://github.com/nodejs/node/pull/14722
Ref: https://github.com/nodejs/node/issues/14717
Ref: https://github.com/nodejs/node/issues/15448


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>