doc: use gcc 12 on AIX for Node.js >=23
Use gcc 12 to build the official binaries for Node.js 23 onwards on AIX. Note that this will require libstdc++12
, available from the AIX toolbox.
Refs: https://github.com/nodejs/build/issues/3806 Refs: https://github.com/nodejs/build/pull/3858 Refs: https://github.com/nodejs/node/pull/54081