[FEATURE]fastjson2中feature期望加入fastjson1的AllowArbitraryCommas

### 请描述您的需求或者改进建议
fastjson2中featrue期望加入fastjson1的AllowArbitraryCommas

### 请描述你建议的实现方案
fastjson2中featrue期望加入fastjson1的AllowArbitraryCommas

### 描述您考虑过的替代方案

#### 附加信息

Start by comparing fastjson1's AllowArbitraryCommas behavior with fastjson2's feature configuration and parser handling. Identify the relevant parser entry points and tests, then verify that fastjson2 accepts the same arbitrary-comma inputs and that regression coverage demonstrates compatibility.

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