[BUG]序列化结果反序列化后存在$ref引用

> ### 问题描述 [https://github.com/alibaba/fastjson2/issues/999](url)
> ### 补充 序列化时加上SerializerFeature.DisableCircularReferenceDetect序列化的结果反序列化时的确不存在$ref,但如果被序列化的对象中包含循环引用，那么序列化这一步就会失败，也就没法反序列化了

Start with the linked issue 999 and the SerializerFeature.DisableCircularReferenceDetect behavior. Reproduce serialization and deserialization with an object containing circular references, then compare the resulting JSON and verify the $ref behavior described in this issue.

Written by the indexing model from the issue text.