url: simplify constructor URLSearchParams. Remove needless check null

PR-URL: #18700
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/url.js

@@ -98,8 +98,7 @@ class URLSearchParams {
   constructor(init = undefined) {
     if (init === null || init === undefined) {
       this[searchParams] = [];
-    } else if ((typeof init === 'object' && init !== null) ||
-               typeof init === 'function') {
+    } else if (typeof init === 'object' || typeof init === 'function') {
       const method = init[Symbol.iterator];
       if (method === this[Symbol.iterator]) {
         // While the spec does not have this branch, we can use it as a