test: remove common.PORT from parallel tests

`common.PORT` should not be used in parallel tests because another test
may experience a collision with `common.PORT` when using port 0 to get
an open port. This has been observed to result in test failures in CI.

PR-URL: https://github.com/nodejs/node/pull/17410


Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Lance Ball <lball@redhat.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>