It used to return `$-1` in RESP2, now we will return `*-1`.
This is a bug in redis 6.2 when COUNT was added, the `COUNT`
option was introduced in #8179. Fix#10089.
the documentation of [LPOP](https://redis.io/commands/lpop) says
```
When called without the count argument:
Bulk string reply: the value of the first element, or nil when key does not exist.
When called with the count argument:
Array reply: list of popped elements, or nil when key does not exist.
```
39feee8e3a