src: include large pages source unconditionally

Restrict the usage of the C preprocessor directive enabling large
pages support to the large pages implementation. This cleans up the
code in src/node.cc.

PR-URL: https://github.com/nodejs/node/pull/31904


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>