test: add ref comment to test-regress-GH-814_2

Because the GitHub issue referred to by the test name is in an old
repository, put a link to it in a comment in
test/pummel/test-regress-GH-814_2.js.

PR-URL: https://github.com/nodejs/node/pull/34516


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>