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