test: refactor common.PORT to random port

Addresses issue discussed in #12376 (closed)

Test changed: test/parallel/test-tls-client-default-ciphers.js

This is my first contribution! #goodnessSquad

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)