src: fix largepages regression

During the addition of macOS support for large pages, a `memcpy` ended
up under the wrong preprocessor directive. As a result, the newly
allocated large pages were not initialized with a copy of the text
section.

Thanks to Suresh Srinivas <suresh.srinivas@intel.com>!

PR-URL: https://github.com/nodejs/node/pull/29914


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>