Investigate flaky test test-http-chunked-304 on SmartOS

[Trott]

Fails about 0.03% of the time. Looks similar to #3830 and a similar fix may be in order.

https://ci.nodejs.org/job/node-stress-single-test/3/nodes=smartos14-32/console

[claudiorodriguez]

@Trott Would appreciate your feedback on the PR. I hope you don't mind I more or less cloned your commit message and code comment.
Gotta say I'm a bit iffy on those listeners being bound inside the 'connect' listener - that's how I found it so I went for consistency. I can of course extract them if it could be an issue.