test: dynamic port in parallel regress tests

Removed common.PORT from test-regress-GH-5051 and
test-regress-GH-5727 in order to eliminate the possibility
of port collision.

Refs: https://github.com/nodejs/node/issues/12376
PR-URL: https://github.com/nodejs/node/pull/12639
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>

test/parallel/test-regress-GH-5051.js

@@ -12,20 +12,22 @@ agent.maxSockets = 0;
 
 // localAddress is used when naming requests / sockets
 // while using the Legacy API
-agent.addRequest(req, 'localhost', common.PORT, '127.0.0.1');
+// port 8080 is hardcoded since this does not create a network connection
+agent.addRequest(req, 'localhost', 8080, '127.0.0.1');
 assert.strictEqual(Object.keys(agent.requests).length, 1);
 assert.strictEqual(
   Object.keys(agent.requests)[0],
-  'localhost:' + common.PORT + ':127.0.0.1');
+  'localhost:8080:127.0.0.1');
 
 // path is *not* used when naming requests / sockets
+// port 8080 is hardcoded since this does not create a network connection
 agent.addRequest(req, {
   host: 'localhost',
-  port: common.PORT,
+  port: 8080,
   localAddress: '127.0.0.1',
   path: '/foo'
 });
 assert.strictEqual(Object.keys(agent.requests).length, 1);
 assert.strictEqual(
   Object.keys(agent.requests)[0],
-  'localhost:' + common.PORT + ':127.0.0.1');
+  'localhost:8080:127.0.0.1');

test/parallel/test-regress-GH-5727.js

@@ -6,9 +6,9 @@ const net = require('net');
 const invalidPort = -1 >>> 0;
 const errorMessage = /"port" argument must be >= 0 and < 65536/;
 
-net.Server().listen(common.PORT, function() {
+net.Server().listen(0, function() {
   const address = this.address();
-  const key = `${address.family.slice(-1)}:${address.address}:${common.PORT}`;
+  const key = `${address.family.slice(-1)}:${address.address}:0`;
 
   assert.strictEqual(this._connectionKey, key);
   this.close();