deps: V8: forward declaration of `Rtl*FunctionTable`

This should be semver-patch since actual invocation is version
conditional.

PR-URL: https://github.com/nodejs/node/pull/27375


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>