test: fix parallel/test-net-socket-local-address

[bnoordhuis]

Fix flakiness where the client sometimes closed the server before the
server had the chance to process the outstanding client connection.
Make the server close itself instead.

Fixes: #2475

R=@Trott

CI: https://ci.nodejs.org/job/node-test-pull-request/885/
Stress test: https://ci.nodejs.org/job/node-stress-single-test/94/

[Trott]

Stress test on Windows 2012r2 because the current version of this test is flaky there too: https://ci.nodejs.org/job/node-stress-single-test/96/

[Trott]

Previous FreeBSD stress test did not launch properly due to some CI issue, but it's working now at https://ci.nodejs.org/job/node-stress-single-test/97/nodes=freebsd102-64/

[Trott]

@bnoordhuis It looks like this fix works for Windows but does not fix the issue on FreeBSD. 74 failures out of 311 runs so far on the stress test.

[Trott]

For comparison, here's the stress test with the solution in #4052: https://ci.nodejs.org/job/node-stress-single-test/103/nodes=freebsd102-64/console (So far, 135 runs without a failure...)

[bnoordhuis]

Stress test with one more tweak (hope I got the CI parameters right): https://ci.nodejs.org/job/node-stress-single-test/118/nodes=freebsd102-64/console

[bnoordhuis]

Okay, that clearly didn't fix it.

[bnoordhuis]

Closing, superseded by #4109.