net: replace destroySoon with socket.end()

As per @ronag suggestion, destroySoon is considered
obsolete, all of its functionnality having been
implemented by Writeable.end()

Refs: #36205

Author: mmomtchev

lib/_http_client.js

@@ -709,11 +709,7 @@ function responseOnEnd() {
 
   if (!req.shouldKeepAlive) {
     if (socket.writable) {
-      debug('AGENT socket.destroySoon()');
-      if (typeof socket.destroySoon === 'function')
-        socket.destroySoon();
-      else
-        socket.end();
+      socket.end();
     }
     assert(!socket.writable);
   } else if (req.finished && !this.aborted) {

lib/_http_server.js

@@ -814,11 +814,7 @@ function resOnFinish(req, res, socket, state, server) {
   process.nextTick(emitCloseNT, res);
 
   if (res._last) {
-    if (typeof socket.destroySoon === 'function') {
-      socket.destroySoon();
-    } else {
-      socket.end();
-    }
+    socket.end();
   } else if (state.outgoing.length === 0) {
     if (server.keepAliveTimeout && typeof socket.setTimeout === 'function') {
       socket.setTimeout(server.keepAliveTimeout);