**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))



query_plan.getCurrentDataStream(),
        output_order_descr,
        settings.max_block_size,
        limit,
        settings.max_bytes_before_remerge_sort,
        settings.remerge_sort_lowered_memory_bytes_ratio,
        settings.max_bytes_before_external_sort,
        context->getTemporaryVolume(),
        settings.min_free_disk_space_for_temporary_data);
    merge_sorting_step->setStepDescription("Merge sorted blocks for ORDER BY");
    query_plan.addStep(std::move(merge_sorting_step));
    
    executeMergeSorted(query_plan, output_order_descr, limit, "for ORDER BY");
}
void InterpreterSelectQuery::executeMergeSorted(QueryPlan & query_plan, const std::string & description)
{
    auto & query = getSelectQuery();
    SortDescription order_descr = getSortDescription(query, context);
    UInt64 limit = getLimitForSorting(query, context);
    executeMergeSorted(query_plan, order_descr, limit, description);
}
void InterpreterSelectQuery::executeMergeSorted(QueryPlan & query_plan, const SortDescription & sort_description, UInt64 limit, const std::string & description)
{
    const Settings & settings = context->getSettingsRef();
    auto merging_sorted
        = std::make_unique<MergingSortedStep>(query_plan.getCurrentDataStream(), sort_description, settings.max_block_size, limit);
    merging_sorted->setStepDescription("Merge sorted streams " + description);
    query_plan.addStep(std::move(merging_sorted));
}
void InterpreterSelectQuery::executeProjection(QueryPlan & query_plan, const ActionsDAGPtr & expression)