GroupBy validation not able to recognize aliased column is a literal

This test `column_alias_queries.go` is currently skipped
```
{
// GMS returns "expression 'dt.two' doesn't appear in the group by expressions", but MySQL will execute
// this query.
Query: "select 1 as a, one + 1 as mod1, dt.* from mytable as t1, (select 1, 2 from mytable) as dt (one, two) where dt.one > 0 group by one;",
// column names: a, mod1, one, two
Expected: []sql.Row{{1, 2, 1, 2}},
}
```

It seems like we're currently unable to see that dt.two resolves to a Literal