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)
```
PaddedPODArray<UInt8> & mask,
    const ColumnPtr & column,
    UInt8 null_value,
    PaddedPODArray<UInt8> * nulls = nullptr)
{
    UInt8 value;
    if (column->onlyNull())
    {
        value = null_value;
        if (nulls)
            std::fill(nulls->begin(), nulls->end(), 1);
    }
    else
        value = column->getBool(0);
    if constexpr (inverted)
        value = !value;
    size_t ones_count = 0;
    if (value)
        ones_count = countBytesInFilter(mask);
    else
        std::fill(mask.begin(), mask.end(), 0);
    return {.has_ones = ones_count > 0, .has_zeros = ones_count != mask.size()};
}
template <bool inverted>
MaskInfo extractMaskImpl(