**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))



{
    auto actions_dag = std::make_shared<ActionsDAG>(aggregated_columns);
    NamesWithAliases result_columns;
    Names result_names;
    ASTs asts;
    if (const auto * node = query->as<ASTExpressionList>())
        asts = node->children;
    else
        asts = ASTs(1, query);
    for (const auto & ast : asts)
    {
        std::string name = ast->getColumnName();
        std::string alias;
        if (add_aliases)
            alias = ast->getAliasOrColumnName();
        else
            alias = name;
        result_columns.emplace_back(name, alias);
        result_names.push_back(alias);
        getRootActions(ast, false, actions_dag);
    }
    if (add_aliases)
    {
        if (project_result)
            actions_dag->project(result_columns);
        else