[BUG]JSON.parseArray转JSONObject，程序直接挂了

### 问题描述
*简要描述您碰到的问题。*

### 环境信息
*请填写以下信息：*

- OS信息： MacOS
- JDK信息：java version "1.8.0_361"
- 版本信息：Fastjson2 2.0.1

### 重现步骤
1. 使用 `static List parseArray(String str, Type itemType)` 方法
2. 输入 `null` 数据
3. 出现程序直接挂掉的错误
```java
data.getLeaveImageArray() 如果 leaveImageArray(String类型) 为null的情况下，调用 JSON.parseArray 方法
List images = JSON.parseArray(data.getLeaveImageArray(), JSONObject.class);
```

### 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
Stack: [0x000000030ec8c000,0x000000030ed8c000], sp=0x000000030ed8b340, free space=1020k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.dylib+0x579a50] Unsafe_GetObject+0x60
J 2923 sun.misc.Unsafe.getObject(Ljava/lang/Object;J)Ljava/lang/Object; (0 bytes) @ 0x000000010c3df13e [0x000000010c3df080+0xbe]
j com.alibaba.fastjson2.util.JDKUtils.getCharArray(Ljava/lang/String;)[C+13
j com.alibaba.fastjson2.JSONReader.of(Ljava/lang/String;)Lcom/alibaba/fastjson2/JSONReader;+96
j com.alibaba.fastjson2.JSON.parseArray(Ljava/lang/String;Ljava/lang/reflect/Type;)Ljava/util/List;+20
j com.ydt.share.mq.CarOutConsumer.onMessage(Lcom/ydt/core/rocketmq/enums/RocketmqMsg;)V+147
j com.ydt.share.mq.CarOutConsumer.onMessage(Ljava/lang/Object;)V+5
j org.apache.rocketmq.spring.support.DefaultRocketMQListenerContainer.handleMessage(Lorg/apache/rocketmq/common/message/MessageExt;)V+16
j org.apache.rocketmq.spring.support.DefaultRocketMQListenerContainer.access$100(Lorg/apache/rocketmq/spring/support/DefaultRocketMQListenerContainer;Lorg/apache/rocketmq/common/message/MessageExt;)V+2
j org.apache.rocketmq.spring.support.DefaultRocketMQListenerContainer$DefaultMessageListenerConcurrently.consumeMessage(Ljava/util/List;Lorg/apache/rocketmq/client/consumer/listener/ConsumeConcurrentlyContext;)Lorg/apache/rocketmq/client/consumer/listener/ConsumeConcurrentlyStatus;+50
j org.apache.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run()V+290
j java.util.concurrent.Executors$RunnableAdapter.call()Ljava/lang/Object;+4
j java.util.concurrent.FutureTask.run$$$capture()V+42
j java.util.concurrent.FutureTask.run()V+5
j java.util.concurrent.ThreadPoolExecutor.runWorker(Ljava/util/concurrent/ThreadPoolExecutor$Worker;)V+95
j java.util.concurrent.ThreadPoolExecutor$Worker.run()V+5
j java.lang.Thread.run()V+11
v ~StubRoutines::call_stub
V [libjvm.dylib+0x2d858b] JavaCalls::call_helper(JavaValue*, methodHandle*, JavaCallArguments*, Thread*)+0x689
V [libjvm.dylib+0x2d73ee] JavaCalls::call_virtual(JavaValue*, KlassHandle, Symbol*, Symbol*, JavaCallArguments*, Thread*)+0x14a
V [libjvm.dylib+0x2d75cf] JavaCalls::call_virtual(JavaValue*, Handle, KlassHandle, Symbol*, Symbol*, Thread*)+0x57
V [libjvm.dylib+0x3447f3] thread_entry(JavaThread*, Thread*)+0x78
V [libjvm.dylib+0x562bd0] JavaThread::thread_main_inner()+0x82
V [libjvm.dylib+0x562a8f] JavaThread::run()+0x19d
V [libjvm.dylib+0x48fb3b] java_start(Thread*)+0xfa
C [libsystem_pthread.dylib+0x6259] _pthread_start+0x7d
C [libsystem_pthread.dylib+0x1c7b] thread_start+0xf
C 0x0000000000000000

#### 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.parseArray(String, Type) and reproduce the reported null-string input with JSONObject.class on the stated Fastjson2 version. The issue does not specify the intended result, so first confirm the expected null behavior; done means that behavior is defined and the input no longer causes the reported JVM crash.

Written by the indexing model from the issue text.