LibJS: Fix that functions in module did not look for var declarations

Author: https://github.com/davidot
Commit: 67865306d3
Pull-request: https://github.com/SerenityOS/serenity/pull/16073
Issue: https://github.com/SerenityOS/serenity/issues/16044
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibJS/Tests/modules/basic-modules.js

@@ -239,3 +239,9 @@ describe("failing modules cascade", () => {
         );
     });
 });
+
+describe("scoping in modules", () => {
+    test("functions within functions", () => {
+        expectModulePassed("./function-in-function.mjs");
+    });
+});