[BUG]arm64 xmx8g JSON.config(JSONWriter.Feature.WriteMapNullValue); 有问题

### 问题描述
*简要描述您碰到的问题。*
JSON.config(JSONWriter.Feature.WriteMapNullValue);
```
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x0000ffffa90c9604, pid=354216, tid=0x0000fffe845fa120
#
# JRE version: Java(TM) SE Runtime Environment (8.0_411) (build 1.8.0_411-b09)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.411-b09 mixed mode linux-aarch64 compressed oops)
# Problematic frame:
# J 7868 C2 java.util.LinkedHashMap$LinkedEntryIterator.next()Ljava/lang/Object; (5 bytes) @ 0x0000ffffa90c9604 [0x0000ffffa90c95c0+0x44]
```
### 环境信息
*请填写以下信息：*
arm64 xmx8g
JRE version: Java(TM) SE Runtime Environment (8.0_411) (build 1.8.0_411-b09)
- 版本信息：[e.g.：Fastjson2 2.0.49]

### 重现步骤
*如何操作可以重现该问题：*

1. 使用 `xxx.xxx` 方法
2. 输入 `...` 数据
3. 出现 `...` 错误
```java
//可在此输入示例代码
```

### 期待的正确结果
*对您期望发生的结果进行清晰简洁的描述。*

### 相关日志输出
*请复制并粘贴任何相关的日志输出。*

#### 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）。*

Start at JSON.config(JSONWriter.Feature.WriteMapNullValue) and reproduce the reported SIGSEGV on arm64 with Java 8.0.411, using the LinkedHashMap$LinkedEntryIterator.next frame as the failure point. The issue has no concrete reproduction code or input, so first establish a minimal reproducer; done means the crash is isolated and a regression test demonstrates the corrected behavior.

Written by the indexing model from the issue text.