worker: unroll file extension regexp

Refs: nodejs#31662 (comment)

PR-URL: nodejs#31779
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/internal/worker.js

@@ -104,7 +104,7 @@ class Worker extends EventEmitter {
       filename = path.resolve(filename);
 
       const ext = path.extname(filename);
-      if (!/^\.[cm]?js$/.test(ext)) {
+      if (ext !== '.js' && ext !== '.mjs' && ext !== '.cjs') {
         throw new ERR_WORKER_UNSUPPORTED_EXTENSION(ext);
       }
     }