http: use more destructuring

PR-URL: #19481
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jackson Tian <shyvo1987@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/http.js

@@ -21,14 +21,17 @@
 
 'use strict';
 
-const agent = require('_http_agent');
+const { Agent, globalAgent } = require('_http_agent');
 const { ClientRequest } = require('_http_client');
-const common = require('_http_common');
-const incoming = require('_http_incoming');
-const outgoing = require('_http_outgoing');
-const server = require('_http_server');
-
-const { Server } = server;
+const { methods } = require('_http_common');
+const { IncomingMessage } = require('_http_incoming');
+const { OutgoingMessage } = require('_http_outgoing');
+const {
+  _connectionListener,
+  STATUS_CODES,
+  Server,
+  ServerResponse
+} = require('_http_server');
 
 function createServer(requestListener) {
   return new Server(requestListener);
@@ -45,16 +48,16 @@ function get(options, cb) {
 }
 
 module.exports = {
-  _connectionListener: server._connectionListener,
-  METHODS: common.methods.slice().sort(),
-  STATUS_CODES: server.STATUS_CODES,
-  Agent: agent.Agent,
+  _connectionListener,
+  METHODS: methods.slice().sort(),
+  STATUS_CODES,
+  Agent,
   ClientRequest,
-  globalAgent: agent.globalAgent,
-  IncomingMessage: incoming.IncomingMessage,
-  OutgoingMessage: outgoing.OutgoingMessage,
+  globalAgent,
+  IncomingMessage,
+  OutgoingMessage,
   Server,
-  ServerResponse: server.ServerResponse,
+  ServerResponse,
   createServer,
   get,
   request