buffer: avoid use of arguments

Avoid use of arguments in Buffer.prototype.toString()

PR-URL: https://github.com/nodejs/node/pull/11358
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

lib/buffer.js

@@ -503,12 +503,12 @@ Buffer.prototype.copy = function(target, targetStart, sourceStart, sourceEnd) {
   return binding.copy(this, target, targetStart, sourceStart, sourceEnd);
 };
 
-Buffer.prototype.toString = function() {
+Buffer.prototype.toString = function(encoding, start, end) {
   let result;
   if (arguments.length === 0) {
     result = this.utf8Slice(0, this.length);
   } else {
-    result = slowToString.apply(this, arguments);
+    result = slowToString.call(this, encoding, start, end);
   }
   if (result === undefined)
     throw new Error('"toString()" failed');