You have to provide the following information whenever possible.

**Describe the bug**
This query fails with the latest stable version 21.5.5.12. It worked with the last stable version 21.4.7.3.

**Does it reproduce on recent release?**
yes

**How to reproduce**
21.5.5.12

```
SELECT
    label,
    number
FROM
(
    SELECT
        'a' AS label,
        number
    FROM
    (
        SELECT number
        FROM numbers(10)
    )
    UNION ALL
    SELECT
        'b' AS label,
        number
    FROM
    (
        SELECT number
        FROM numbers(10)
    )
)
WHERE number IN
(
    SELECT number
    FROM numbers(5)
)
```

**Expected behavior**
Query should run without errors

**Error message and/or stacktrace**
```
Received exception from server (version 21.5.5):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: Block structure mismatch in Pipe::unitePipes stream: different names of columns:
label String String(size = 0), number UInt64 UInt64(size = 0), 'b' String Const(size = 0, String(size = 1))
label String String(size = 0), number UInt64 UInt64(size = 0), 'a' String Const(size = 0, String(size = 1)).
```

if (all_const)
        {
            size_t num_rows = arguments.empty() ? 0 : arguments.front().column->size();
            column = node.function->execute(arguments, node.result_type, num_rows, true);
        }
        else
        {
            column = node.function_base->getConstantResultForNonConstArguments(arguments, node.result_type);
        }
        
        if (column && isColumnConst(*column))
        {
            
            
            
            if (column->empty())
                column = column->cloneResized(1);
            node.column = std::move(column);
        }
    }
    if (result_name.empty())
    {
        result_name = function->getName() + "(";
        for (size_t i = 0; i < num_arguments; ++i)
        {
            if (i)
                result_name += ", ";
            result_name += node.children[i]->result_name;
        }
        result_name += ")";