**Describe what's wrong**

Query with rollup using same selected field name as the name of underlying column reports structure mismatch

**Does it reproduce on recent release?**

yes

**How to reproduce**

`21.9.2.17`

```sql
CREATE TABLE test
(
    `d` DateTime,
    `a` LowCardinality(String),
    `b` UInt64
)
ENGINE = MergeTree
PARTITION BY toDate(d)
ORDER BY d;

SELECT *
FROM (
    SELECT
        a,
        max((d, b)).2 AS value
    FROM test
    GROUP BY rollup(a)
)
WHERE a <> '';
```

**Expected behavior**

This used to return an ok result on v21.8

**Error message and/or stacktrace**

> Code: 352. DB::Exception: Block structure mismatch in (columns with identical name must have identical structure) stream: different columns:
> notEquals(a, '') LowCardinality(UInt8) ColumnLowCardinality(size = 0, UInt8(size = 0), ColumnUnique(size = 1, UInt8(size = 1)))
> notEquals(a, '') LowCardinality(UInt8) Const(size = 0, ColumnLowCardinality(size = 1, UInt8(size = 1), ColumnUnique(size = 2, UInt8(size = 2)))). (AMBIGUOUS_COLUMN_NAME) (version 21.9.2.17 (official build))



if (new_argument)
                        group_asts[i] = new_argument;
                }
                const auto & column_name = group_asts[i]->getColumnName();
                const auto * node = temp_actions->tryFindInIndex(column_name);
                if (!node)
                    throw Exception("Unknown identifier (in GROUP BY): " + column_name, ErrorCodes::UNKNOWN_IDENTIFIER);
                
                if (getContext()->getClientInfo().distributed_depth == 0 || settings.distributed_group_by_no_merge > 0)
                {
                    
                    if (node->column && isColumnConst(*node->column))
                    {
                        select_query->group_by_with_constant_keys = true;
                        
                        if (!aggregate_descriptions.empty() || size > 1)
                        {
                            if (i + 1 < static_cast<ssize_t>(size))
                                group_asts[i] = std::move(group_asts.back());
                            group_asts.pop_back();
                            --i;
                            continue;
                        }
                    }
                }
                NameAndTypePair key{column_name, node->result_type};
                
                if (!unique_keys.count(key.name))
                {
                    unique_keys.insert(key.name);