LibJS: Uncomment passing tests

Author: https://github.com/BertalanD
Commit: 7ac6af1998
Pull-request: https://github.com/SerenityOS/serenity/pull/20423
Reviewed-by: https://github.com/gmta ✅

Userland/Libraries/LibJS/Tests/syntax/optional-chaining.js

@@ -10,8 +10,7 @@ test("parse optional-chaining", () => {
     expect("a?.b?.``").not.toEval();
     expect("new Foo?.bar").not.toEval();
     expect("new (Foo?.bar)").toEval();
-    // FIXME: This should pass.
-    // expect("(new Foo)?.bar").toEval();
+    expect("(new Foo)?.bar").toEval();
 });
 
 test("evaluate optional-chaining", () => {