remove __ prefix

Author: guybedford

lib/internal/modules/cjs/loader.js

@@ -1420,7 +1420,7 @@ function loadESMFromCJS(mod, filename) {
     // don't have default exports to avoid the unnecessary overhead.
     // If __esModule is already defined, we will also skip the extension
     // to allow users to override it.
-    if (namespace.__cjsUnwrapDefault) {
+    if (namespace.cjsUnwrapDefault) {
       mod.exports = namespace.default;
     } else if (!ObjectHasOwn(namespace, 'default') || ObjectHasOwn(namespace, '__esModule')) {
       mod.exports = namespace;