deps: update V8 postmortem metadata script

This commit updates V8's gen-postmortem-metadata.py script
to fix SmartOS compilation for V8 8.4.

Backport-PR-URL: https://github.com/nodejs/node/pull/34356
PR-URL: https://github.com/nodejs/node/pull/33579


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>