buffer: remove hoisted variable

PR-URL: nodejs#33470
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/buffer.js

@@ -544,7 +544,6 @@ Buffer.isEncoding = function isEncoding(encoding) {
 Buffer[kIsEncodingSymbol] = Buffer.isEncoding;
 
 Buffer.concat = function concat(list, length) {
-  let i;
   if (!ArrayIsArray(list)) {
     throw new ERR_INVALID_ARG_TYPE('list', 'Array', list);
   }
@@ -554,7 +553,7 @@ Buffer.concat = function concat(list, length) {
 
   if (length === undefined) {
     length = 0;
-    for (i = 0; i < list.length; i++) {
+    for (let i = 0; i < list.length; i++) {
       if (list[i].length) {
         length += list[i].length;
       }
@@ -565,7 +564,7 @@ Buffer.concat = function concat(list, length) {
 
   const buffer = Buffer.allocUnsafe(length);
   let pos = 0;
-  for (i = 0; i < list.length; i++) {
+  for (let i = 0; i < list.length; i++) {
     const buf = list[i];
     if (!isUint8Array(buf)) {
       // TODO(BridgeAR): This should not be of type ERR_INVALID_ARG_TYPE.