test: fix pummel/test-net-connect-memleak

A loop that generates a long array is resulting in a RangeError. Moving
to Array.prototype.fill() along with the ** operator instead of using a
loop fixes the issue.

PR-URL: https://github.com/nodejs/node/pull/21658


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>