Investigate flaky test-https-agent-create-connection on multiple platforms

[Trott]

https://ci.nodejs.org/job/node-test-commit-linuxone/4236/nodes=rhel72-s390x/console

not ok 638 parallel/test-https-agent-create-connection
  ---
  duration_ms: 0.120
  severity: fail
  stack: |-
    events.js:163
          throw er; // Unhandled 'error' event
          ^
    
    Error: connect ECONNREFUSED 127.0.0.1:59481
        at Object.exports._errnoException (util.js:986:11)
        at exports._exceptionWithHostPort (util.js:1009:20)
        at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1089:14)

[mscdex]

FWIW I just saw this same test fail, but with different output on the same rhel72-s390x machine:

not ok 637 parallel/test-https-agent-create-connection
  ---
  duration_ms: 0.170
  severity: fail
  stack: |-
    
    assert.js:81
      throw new assert.AssertionError({
      ^
    AssertionError: false == true
        at TLSSocket.socket.on.common.mustCall (/data/iojs/build/workspace/node-test-commit-linuxone/nodes/rhel72-s390x/test/parallel/test-https-agent-create-connection.js:111:5)
        at TLSSocket.<anonymous> (/data/iojs/build/workspace/node-test-commit-linuxone/nodes/rhel72-s390x/test/common.js:452:15)
        at emitOne (events.js:96:13)
        at TLSSocket.emit (events.js:191:7)
        at emitErrorNT (net.js:1280:8)
        at _combinedTickCallback (internal/process/next_tick.js:80:11)
        at process._tickCallback (internal/process/next_tick.js:104:9)

[mscdex]

I should also add that the same stack trace I just posted for the same test has happened on centos5-32 now.

[Trott]

Now Windows: https://ci.nodejs.org/job/node-test-binary-windows/6823/RUN_SUBSET=3,VS_VERSION=vs2015,label=win2008r2/console

not ok 160 parallel/test-https-agent-create-connection 
 ---
  duration_ms: 1.398
  severity: fail
  stack: |-
    events.js:163
          throw er; // Unhandled 'error' event
          ^
    
    Error: connect ECONNREFUSED 127.0.0.1:52212
        at Object.exports._errnoException (util.js:986:11)
        at exports._exceptionWithHostPort (util.js:1009:20)
        at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1089:14)

[Trott]

This is a brand new test as of about two weeks ago. Looping in author, approvers, and testing working group:

@chiiia12 @jasnell @abouthiroppy @nodejs/testing

[santigimeno]

@Trott, proposed fix here: #11649