nullif panics on empty array

[bjchambers]

Describe the bug

#[test]
fn test_null_if_len_0() {
    let primitive_array = arrow::array::new_empty_array(&DataType::Int64);
    let condition: Vec<bool> = vec![];
    let condition_array = BooleanArray::from(condition);
    nullif(primitive_array.as_ref(), &condition_array).unwrap();
}

To Reproduce
Run the above test. Observe a panic.

Expected behavior
No panic. Result should be an empty array.

Additional context

[bjchambers]

@tustvold In debugging, it looks like it still executes the closure in the bitwise unary operator once, and in my case it had 64 ones, so it incremented the valid count by 64. But then len - valid_count causes a panic.

        None => {
            let buffer = arrow::buffer::bitwise_unary_op_helper(&right, right_offset, len, |b| {
                let t = !b;
                valid_count += t.count_ones() as usize;
                t
            });
            // We need to compensate for the additional bits read from the end
            let remainder_len = len % 64;
            if remainder_len != 0 {
                valid_count -= 64 - remainder_len
            }
            buffer
        }

[alamb]

label_issue.py automatically added labels {'arrow'} from #3263