LibJS: Forward receiver value to native property getters/setters

There's no reason why only (user-defined) accessors would have set the
receiver as this value for their getters/setters, this is an oversight.

Libraries/LibJS/Tests/builtins/Reflect/Reflect.set.js

@@ -93,4 +93,10 @@ describe("normal behavior", () => {
         expect(foo.setPropCalled).toBeTrue();
         expect(bar.setPropCalled).toBeTrue();
     });
+
+    test("native setter function", () => {
+        const e = new Error();
+        Reflect.set(Error.prototype, "name", "Foo", e);
+        expect(e.name).toBe("Foo");
+    });
 });