Fuzzer 19. Calling GetValueInternal on a value that is NULL

```sql
SELECT percentile_disc(strftime(DATE '1-11-25',NULL)) WITHIN GROUP (ORDER BY 1 DESC);
-- or
SELECT percentile_cont(CASE 1 WHEN 2 THEN 3 END) WITHIN GROUP (ORDER BY 1 DESC);
```

```
ABORT THROWN BY INTERNAL EXCEPTION: Calling GetValueInternal on a value that is NULL
```