[9.x] Fix undefined constant error when use slot name as key of object

[monurakkaya]

It's solution for #42932

I've described problem in the issue.

With 9.15 and after we cannot use <x-slot :name="$model->name"> because it is rendering as

<?php $__env->slot($model>name, null, []); ?>

instead

<?php $__env->slot($model->name, null, []); ?>

[monurakkaya]

@taylorotwell I’ve added the test which will fail on 9.15 - 9.18 tags.