[BUG] com.alibaba.fastjson2.JSONException: reference path invalid : ..

### 问题描述
反序列化对象的时候报错com.alibaba.fastjson2.JSONException: reference path invalid : ..

at com.alibaba.fastjson2.JSONReader.handleResolveTasks(JSONReader.java:320)
at com.alibaba.fastjson2.JSON.parse(JSON.java:75)
at com.alibaba.fastjson2.JSON.toJSON(JSON.java:3937)

### 环境信息
*请填写以下信息：*

- OS信息： [e.g.：CentOS 8.4.2105 4Core 3.10GHz 16 GB]
- JDK信息： [e.g.：Openjdk 1.8.0_312]
- 版本信息：[e.g.：Fastjson2 2.x.x]

### 重现步骤
*如何操作可以重现该问题：*

```java
@Test
public void test() {
class A {
A a;
String b;

public String getB() {
return b;
}

public A getA() {
return a;
}
}
class Request {
List list;

public List getList() {
return list;
}
}

A a = new A();
a.a = a;
a.b = "test";
List list = new ArrayList<>();
list.add(a);
Request request = new Request();
request.list = list;
System.out.println(JSON.toJSON(request, JSONWriter.Feature.ReferenceDetection));
// System.out.println(JSON.parse(JSON.toJSONString(request,JSONWriter.Feature.ReferenceDetection), JSONReader.Feature.DisableReferenceDetect));

#### 附加信息
*如果你还有其他需要提供的信息，可以在这里填写（可以提供截图、视频等）。*

Reproduce the supplied self-referential A and Request example, then inspect JSONReader.handleResolveTasks, JSON.parse, and JSON.toJSON around the reported stack trace. Add a regression test for ReferenceDetection and verify that the serialized value can be parsed successfully without the DisableReferenceDetect workaround.

Written by the indexing model from the issue text.