test: flaky parallel/test-net-connect-options-allowhalfopen on macOS & freeBSD

[refack]

• Version: master
• Platform: macOS,freeBSD
• Subsystem: test

https://ci.nodejs.org/job/node-test-commit-freebsd/8933/nodes=freebsd11-x64/tapResults/
https://ci.nodejs.org/job/node-test-commit-osx/9696/nodes=osx1010/tapResults/

739	parallel/test-net-connect-options-allowhalfopen	
duration_ms	
0.341
severity	
fail
stack	
Mismatched serverOnConnection function calls. Expected 6, actual 7.
    at forAllClients (/Users/iojs/build/workspace/node-test-commit-osx/nodes/osx1010/test/parallel/test-net-connect-options-allowhalfopen.js:44:38)
    at Object.<anonymous> (/Users/iojs/build/workspace/node-test-commit-osx/nodes/osx1010/test/parallel/test-net-connect-options-allowhalfopen.js:55:21)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Function.Module.runMain (module.js:605:10)
    at startup (bootstrap_node.js:144:16)
Mismatched <anonymous> function calls. Expected 1, actual 0.
    at Server.serverOnConnection (/Users/iojs/build/workspace/node-test-commit-osx/nodes/osx1010/test/parallel/test-net-connect-options-allowhalfopen.js:61:30)
    at Server.<anonymous> (/Users/iojs/build/workspace/node-test-commit-osx/nodes/osx1010/test/common/index.js:460:15)
    at emitOne (events.js:115:13)
    at Server.emit (events.js:210:7)
    at TCP.onconnection (net.js:1519:8)
Server starts at localhost:63140
'connect' emitted on Client 0
1 'connection' emitted on server
Server has sent 1 FIN
2 'connection' emitted on server
Server has sent 2 FIN
3 'connection' emitted on server
Server has sent 3 FIN
4 'connection' emitted on server
Server has sent 4 FIN
'connect' emitted on Client 1
'connect' emitted on Client 2
5 'connection' emitted on server
Server has sent 5 FIN
6 'connection' emitted on server
Server has sent 6 FIN
7 'connection' emitted on server
Server has sent 7 FIN
'connect' emitted on Client 3
'connect' emitted on Client 4
'connect' emitted on Client 5
Server recieved FIN sent by No. undefined
No. 0 client received FIN
No. 0 client sent FIN, 1 have been sent
No. 1 client received FIN
No. 1 client sent FIN, 2 have been sent
No. 2 client received FIN
No. 2 client sent FIN, 3 have been sent
No. 3 client received FIN
No. 3 client sent FIN, 4 have been sent
No. 4 client received FIN
No. 4 client sent FIN, 5 have been sent
No. 5 client received FIN
No. 5 client sent FIN, 6 have been sent
1 server connection is started by client No. 0
2 server connection is started by client No. 1
3 server connection is started by client No. 2
4 server connection is started by client No. 3
5 server connection is started by client No. 4
6 server connection is started by client No. 5
No. 5 connection has been closed by both sides, 1 clients have closed
No. 4 connection has been closed by both sides, 2 clients have closed
No. 3 connection has been closed by both sides, 3 clients have closed
No. 2 connection has been closed by both sides, 4 clients have closed
No. 1 connection has been closed by both sides, 5 clients have closed
No. 0 connection has been closed by both sides, 6 clients have closed
Server recieved FIN sent by No. 0
Server recieved FIN sent by No. 1
Server recieved FIN sent by No. 2
Server recieved FIN sent by No. 3
Server recieved FIN sent by No. 4
Server recieved FIN sent by No. 5
No. 4 connection is closing server: 7 FIN received by server, 6 FIN received by client, 6 FIN sent by client, 7 FIN sent by server
Server has been closed: 7 FIN received by server, 6 FIN received by client, 6 FIN sent by client, 7 FIN sent by server

[refack]

Maybe Ref: #12376

[refack]

This test is OK, it's another test (#12950) that leaks a connection into this