test: don't connect to :: (use localhost instead)

If a test does http.listen(0) or net.listen(0),
http.listen(0).address().address returns '::'. Some machines will
resolve this to localhost, but not all. Every machine should have
localhost defined in /etc/hosts (or equivalent), so it should always
resolve.

Fixes: #7291

test/gc/test-net-timeout.js

@@ -36,7 +36,7 @@ function getall() {
     return;
 
   (function() {
-    var req = net.connect(server.address().port, server.address().address);
+    var req = net.connect(server.address().port);
     req.resume();
     req.setTimeout(10, function() {
       //console.log('timeout (expected)')

test/parallel/test-http-status-reason-invalid-chars.js

@@ -3,7 +3,6 @@
 const common = require('../common');
 const assert = require('assert');
 const http = require('http');
-const net = require('net');
 
 function explicit(req, res) {
   assert.throws(() => {
@@ -34,8 +33,7 @@ const server = http.createServer((req, res) => {
     implicit(req, res);
   }
 }).listen(0, common.mustCall(() => {
-  const addr = server.address().address;
-  const hostname = net.isIPv6(addr) ? `[${addr}1]` : addr;
+  const hostname = 'localhost';
   const url = `http://${hostname}:${server.address().port}`;
   let left = 2;
   const check = common.mustCall((res) => {