doc: use test username instead of real

PR-URL: #35611
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Harshitha K P <harshitha014@gmail.com>

doc/api/process.md

@@ -1422,7 +1422,7 @@ Use care when dropping privileges:
 
 ```js
 console.log(process.getgroups());         // [ 0 ]
-process.initgroups('bnoordhuis', 1000);   // switch user
+process.initgroups('nodeuser', 1000);     // switch user
 console.log(process.getgroups());         // [ 27, 30, 46, 1000, 0 ]
 process.setgid(1000);                     // drop root gid
 console.log(process.getgroups());         // [ 27, 30, 46, 1000 ]