src: merge debug-only `SealHandleScope`s

Instead of repeating the same `#ifdef DEBUG` + `SealHandleScope`
pattern over and over, create an utility that does this for us.

PR-URL: https://github.com/nodejs/node/pull/26459


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>