src: skip warnings for our own deprecated APIs

This makes the compiler not emit deprecation warnings for places
where we use (or, in the case of non-functions, implement) our own
deprecated public C++ APIs.

PR-URL: https://github.com/nodejs/node/pull/22666


Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>