Range based FOR is broken with a DO SUSPEND without BEGIN...END

Firebird-6.0.0.863-0-45be57b-windows-x64

```sql
execute block
returns (i int)
as
begin
  for i = 1 to 3 do suspend;
end
```

Actual result:
```
           I
============
           1
```

Expected result:
```
           I
============
           1
           2
           3
```