http: remove pointless use of arguments

PR-URL: https://github.com/nodejs/node/pull/10664
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/_http_outgoing.js

@@ -382,8 +382,8 @@ OutgoingMessage.prototype.setHeader = function setHeader(name, value) {
 
 
 OutgoingMessage.prototype.getHeader = function getHeader(name) {
-  if (arguments.length < 1) {
-    throw new Error('"name" argument is required for getHeader(name)');
+  if (typeof name !== 'string') {
+    throw new TypeError('"name" argument must be a string');
   }
 
   if (!this._headers) return;
@@ -393,8 +393,8 @@ OutgoingMessage.prototype.getHeader = function getHeader(name) {
 
 
 OutgoingMessage.prototype.removeHeader = function removeHeader(name) {
-  if (arguments.length < 1) {
-    throw new Error('"name" argument is required for removeHeader(name)');
+  if (typeof name !== 'string') {
+    throw new TypeError('"name" argument must be a string');
   }
 
   if (this._header) {