test: fix spurious EADDRINUSE in test-https-strict

[Trott]

Checklist

• tests and code linting passes
• the commit message follows commit guidelines

Affected core subsystem(s)

test https

Description of change

test-https-strict sometimes fails with EADDRINUSE in CI. Remove use of
common.PORT to make the test resistant from side effects from other
tests that may have not freed up the port.

Example CI failure: https://ci.nodejs.org/job/node-test-commit-osx/3545/nodes=osx1010/console

not ok 564 parallel/test-https-strict
# {}
# events.js:160
#       throw er; // Unhandled 'error' event
#       ^
# 
# Error: listen EADDRINUSE :::12448
#     at Object.exports._errnoException (util.js:1007:11)
#     at exports._exceptionWithHostPort (util.js:1030:20)
#     at Server._listen2 (net.js:1253:14)
#     at listen (net.js:1289:10)
#     at Server.listen (net.js:1385:5)
#     at Object.<anonymous> (/Users/iojs/build/workspace/node-test-commit-osx/nodes/osx1010/test/parallel/test-https-strict.js:74:9)
#     at Module._compile (module.js:541:32)
#     at Object.Module._extensions..js (module.js:550:10)
#     at Module.load (module.js:458:32)
#     at tryModuleLoad (module.js:417:12)
  ---
  duration_ms: 0.276

/cc @nodejs/testing @mscdex

[mscdex]

CI: https://ci.nodejs.org/job/node-stress-single-test/745/

LGTM

[addaleax]

LGTM

[cjihrig]

LGTM

[Trott]

CI: https://ci.nodejs.org/job/node-test-pull-request/2884/

[Trott]

Landed in 2f417c3

[MylesBorins]

@Trott lts?

[Trott]

@thealphanerd If it lands cleanly, yes.

[MylesBorins]

this is landing cleanly but causing failures. Didn't dig in, feel free to look into it rich.