dns: name generated functions

PR-URL: #14518
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

lib/dns.js

@@ -253,7 +253,7 @@ class Resolver {
 }
 
 function resolver(bindingName) {
-  return function query(name, /* options, */ callback) {
+  function query(name, /* options, */ callback) {
     var options;
     if (arguments.length > 2) {
       options = callback;
@@ -275,7 +275,9 @@ function resolver(bindingName) {
     var err = this._handle[bindingName](req, name);
     if (err) throw errnoException(err, bindingName);
     return req;
-  };
+  }
+  Object.defineProperty(query, 'name', { value: bindingName });
+  return query;
 }
 
 var resolveMap = Object.create(null);