src: remove identical V macro

This commit removes one of the V macros in IsolateData::MemoryInfo as
they are identical as far as I can tell.

PR-URL: https://github.com/nodejs/node/pull/36427


Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>