**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))



current_totals.reserve(header.columns());
    for (const auto & elem : header)
    {
        MutableColumnPtr new_column = elem.type->createColumn();
        elem.type->insertDefaultInto(*new_column);
        current_totals.emplace_back(std::move(new_column));
    }
}
IProcessor::Status TotalsHavingTransform::prepare()
{
    if (!finished_transform)
    {
        auto status = ISimpleTransform::prepare();
        if (status != Status::Finished)
            return status;
        finished_transform = true;
    }
    auto & totals_output = getTotalsPort();
    
    if (totals_output.isFinished())
        return Status::Finished;
    if (!totals_output.canPush())
        return Status::PortFull;
    if (!totals)
        return Status::Ready;
    totals_output.push(std::move(totals));
    totals_output.finish();
    return Status::Finished;
}
void TotalsHavingTransform::work()