Feat allow special cmd

[wzzssb]

该变动为了保留客户端原始命令，可以让使用者在aof_sync阶段，可以修改客户端输入的命令(大小写)来进行制定的过滤或者特殊处理，并且保留原逻辑中的根据大写命令来获取命令组相关信息能力

detail #943

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[suxb201]

你是讲 DB 自己产生的是 DEL，但是你们自己调用的是 del 对吗？不建议这样搞，有点太 hack 了。

[wzzssb]

你是讲 DB 自己产生的是 DEL，但是你们自己调用的是 del 对吗？不建议这样搞，有点太 hack 了。

是的