url: remove unused kFormat from url

PR-URL: #46867
Backport-PR-URL: #48345
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>

lib/internal/url.js

@@ -103,7 +103,6 @@ const FORWARD_SLASH = /\//g;
 
 const context = Symbol('context');
 const searchParams = Symbol('query');
-const kFormat = Symbol('format');
 
 const updateActions = {
   kProtocol: 0,
@@ -815,7 +814,6 @@ class URL {
 }
 
 ObjectDefineProperties(URL.prototype, {
-  [kFormat]: { __proto__: null, configurable: false, writable: false },
   [SymbolToStringTag]: { __proto__: null, configurable: true, value: 'URL' },
   toString: kEnumerableProperty,
   href: kEnumerableProperty,