**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.

{
    RewriteFunctionToSubcolumnVisitor::Data data{metadata_snapshot};
    RewriteFunctionToSubcolumnVisitor(data).visit(query);
}
std::shared_ptr<ASTFunction> getQuantileFuseCandidate(const String & func_name, std::vector<ASTPtr *> & functions)
{
    if (functions.size() < 2)
        return nullptr;
    const auto & common_arguments = (*functions[0])->as<ASTFunction>()->arguments->children;
    auto func_base = makeASTFunction(GatherFunctionQuantileData::getFusedName(func_name));
    func_base->arguments->children = common_arguments;
    func_base->parameters = std::make_shared<ASTExpressionList>();
    for (const auto * ast : functions)
    {
        assert(ast && *ast);
        const auto * func = (*ast)->as<ASTFunction>();
        assert(func && func->parameters->as<ASTExpressionList>());
        const ASTs & parameters = func->parameters->as<ASTExpressionList &>().children;
        if (parameters.size() != 1)
            return nullptr; 
        func_base->parameters->children.push_back(parameters[0]);
    }
    return func_base;
}
void optimizeFuseQuantileFunctions(ASTPtr & query)