test: fix flaky test-net-GH-5504

The test is failing on `SmartOS` quite often. Removing the timeout seems
to fix it.

Fixes: https://github.com/nodejs/node/issues/8930
PR-URL: https://github.com/nodejs/node/pull/9461
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

test/sequential/test-net-GH-5504.js

@@ -48,14 +48,6 @@ function parent() {
   var spawn = require('child_process').spawn;
   var node = process.execPath;
 
-  setTimeout(function() {
-    if (s) s.kill();
-    if (c) c.kill();
-    setTimeout(function() {
-      throw new Error('hang');
-    });
-  }, common.platformTimeout(2000)).unref();
-
   var s = spawn(node, [__filename, 'server'], {
     env: Object.assign(process.env, {
       NODE_DEBUG: 'net'