lib: add an alias at addListener on Server connection socket

lib/_http_server.js

@@ -394,6 +394,7 @@ function connectionListenerInternal(server, socket) {
 
   // Override on to unconsume on `data`, `readable` listeners
   socket.on = socketOnWrap;
+  socket.addListener = socket.on;
 
   // We only consume the socket if it has never been consumed before.
   if (socket._handle && socket._handle.isStreamBase &&
@@ -744,7 +745,9 @@ function unconsume(parser, socket) {
 function socketOnWrap(ev, fn) {
   const res = net.Socket.prototype.on.call(this, ev, fn);
   if (!this.parser) {
+    this.prependListener = net.Socket.prototype.prependListener;
     this.on = net.Socket.prototype.on;
+    this.addListener = this.on;
     return res;
   }
 

test/parallel/test-http-server-unconsume.js

@@ -14,6 +14,10 @@ const server = http.createServer(function(req, res) {
     received += data;
   });
 
+  assert.strictEqual(req.socket.on, req.socket.addListener);
+  assert.strictEqual(req.socket.prependListener,
+                     net.Socket.prototype.prependListener);
+
   server.close();
 }).listen(0, function() {
   const socket = net.connect(this.address().port, function() {