src: remove duplicate logic for getting buffer

We were fetching the buffer from the float array to send out the
response in js land, however that logic is being duplicated in
node_process.h. Now they will be using an inline to fetch the array
buffers and making it more generic.

PR-URL: https://github.com/nodejs/node/pull/34553


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>