For example, if I use UInt8 constant for if condition then only one branch is evaluated:
```sql
SELECT if(1, 'success', throwIf(1, 'Executing FALSE branch'))

┌─'success'─┐
│ success   │
└───────────┘

1 rows in set. Elapsed: 0.003 sec.
```

But if I use some constant expression, then both branches are evaluated:
```sql
SELECT if(empty(''), 'success', throwIf(1, 'Executing FALSE branch'))

0 rows in set. Elapsed: 0.003 sec.

Received exception from server (version 21.12.2):
Code: 395. DB::Exception: Received from localhost:9000. DB::Exception: Executing FALSE branch: While processing if(empty(''), 'success', throwIf(1, 'Executing FALSE branch')). (FUNCTION_THROW_IF_VALUE_IS_NON_ZERO)
```
const ColumnWithTypeAndName & source_col = arguments[source_idx];
            instruction.source_is_short = source_col.column->size() < arguments[0].column->size();
            if (source_col.type->equals(*return_type))
            {
                instruction.source = source_col.column;
            }
            else
            {
                
                converted_columns_holder.emplace_back(castColumn(source_col, return_type));
                instruction.source = converted_columns_holder.back();
            }
            if (instruction.source && isColumnConst(*instruction.source))
                instruction.source_is_constant = true;
            instructions.emplace_back(std::move(instruction));
            if (instructions.back().condition_always_true)
                break;
        }
        MutableColumnPtr res = return_type->createColumn();
        
        if (instructions.size() == 1 && instructions.front().source_is_constant
            && instructions.front().condition_always_true)
        {
            auto & instruction = instructions.front();
            res->insertFrom(assert_cast<const ColumnConst &>(*instruction.source).getDataColumn(), 0);
            return ColumnConst::create(std::move(res), instruction.source->size());
        }
        size_t rows = input_rows_count;
        for (size_t i = 0; i < rows; ++i)
        {