Add a test case of nested empty array values in conditions

```ruby
  Post.where(id: [[]]).to_a
```
Used to fail with a SQL syntax error (until 4.1):

```sql
SELECT ... WHERE id in ();
```
It now properly generate:

```sql
SELECT ... WHERE 1=0;
```

I think it have been fixed in Arel, but I'm not 100% sure.
In any case I think adding a regression test cannot harm