Unexpected `NULL` return values with false filter or empty set

[PavelSafronov]

Doing a select of the form select count(*), 0, 1, 'a', 'b' on a empty set produces unexpected NULL values.
The example below shows two cases:

1. empty set - there are no items in the table yet
2. false filter - there are items in the table, but we filter all of them out

SQL:

use db;

create table test(id int);

-- empty set
select count(*), 0, 1, 'a', 'b'
FROM test;

-- false filter
insert into test values(1),(2),(3);
select count(*), 0, 1, 'a', 'b'
FROM test
where false;

MySQL behavior:

+----------+---+---+---+---+
| count(*) | 0 | 1 | a | b |
+----------+---+---+---+---+
|        0 | 0 | 1 | a | b |
+----------+---+---+---+---+
+----------+---+---+---+---+
| count(*) | 0 | 1 | a | b |
+----------+---+---+---+---+
|        0 | 0 | 1 | a | b |
+----------+---+---+---+---+

dolt behavior:

+----------+------+------+------+------+
| count(*) | 0    | 1    | a    | b    |
+----------+------+------+------+------+
| 0        | NULL | NULL | NULL | NULL |
+----------+------+------+------+------+

Query OK, 3 rows affected (0.00 sec)
+----------+------+------+------+------+
| count(*) | 0    | 1    | a    | b    |
+----------+------+------+------+------+
| 0        | NULL | NULL | NULL | NULL |
+----------+------+------+------+------+

[fulghum]

Looks like this was fixed by dolthub/go-mysql-server#1704