path: change posix.join to use array

Change posix.join to use array.join instead of additional assignment.

PR-URL: #54331
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>

lib/path.js

@@ -1237,20 +1237,20 @@ const posix = {
   join(...args) {
     if (args.length === 0)
       return '.';
-    let joined;
+
+    const path = [];
     for (let i = 0; i < args.length; ++i) {
       const arg = args[i];
       validateString(arg, 'path');
       if (arg.length > 0) {
-        if (joined === undefined)
-          joined = arg;
-        else
-          joined += `/${arg}`;
+        path.push(arg);
       }
     }
-    if (joined === undefined)
+
+    if (path.length === 0)
       return '.';
-    return posix.normalize(joined);
+
+    return posix.normalize(ArrayPrototypeJoin(path, '/'));
   },
 
   /**