**Describe the situation**
multiIf works 10 times slower than If with single condition.

**How to reproduce**
ClickHouse version 21.10

```

SELECT count()
FROM numbers_mt(1000000000)
WHERE NOT ignore(multiIf(number = 0, NULL, toNullable(number)))

┌────count()─┐
│ 1000000000 │
└────────────┘

1 rows in set. Elapsed: 10.267 sec. Processed 1.00 billion rows, 8.00 GB (97.41 million rows/s., 779.25 MB/s.)

SELECT count()
FROM numbers_mt(1000000000)
WHERE NOT ignore(If(number = 0, NULL, toNullable(number)))

┌────count()─┐
│ 1000000000 │
└────────────┘

1 rows in set. Elapsed: 1.010 sec. Processed 1.00 billion rows, 8.00 GB (990.63 million rows/s., 7.93 GB/s.)
```

**Expected performance**
The same performance for multiIf and if.

{
    if (!select_query->join())
        return;
    const auto * table_join = select_query->join()->table_join->as<ASTTableJoin>();
    if (!(table_join && table_join->using_expression_list))
        return;
    ASTs & expression_list = table_join->using_expression_list->children;
    ASTs uniq_expressions_list;
    std::set<String> expressions_names;
    for (const auto & expression : expression_list)
    {
        auto expression_name = expression->getAliasOrColumnName();
        if (expressions_names.find(expression_name) == expressions_names.end())
        {
            uniq_expressions_list.push_back(expression);
            expressions_names.insert(expression_name);
        }
    }
    if (uniq_expressions_list.size() < expression_list.size())
        expression_list = uniq_expressions_list;
}
void optimizeAggregationFunctions(ASTPtr & query)