**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 (settings.optimize_redundant_functions_in_order_by)
        optimizeRedundantFunctionsInOrderBy(select_query, context);
    
    if (settings.optimize_monotonous_functions_in_order_by)
        optimizeMonotonousFunctionsInOrderBy(select_query, context, tables_with_columns, result);
    
    
    
    optimizeDuplicatesInOrderBy(select_query);
    
    if (settings.optimize_if_transform_strings_to_enum)
        transformIfStringsIntoEnum(query);
    
    optimizeLimitBy(select_query);
    
    optimizeUsing(select_query);
    if (settings.optimize_syntax_fuse_functions)
        optimizeFuseQuantileFunctions(query);
    if (settings.optimize_or_like_chain
        && settings.allow_hyperscan
        && settings.max_hyperscan_regexp_length == 0
        && settings.max_hyperscan_regexp_total_length == 0)
    {
        optimizeOrLikeChain(query);
    }
}
}