Updating a Nullable column value by using alter .... where ... causes to set another value!

ClickHouse version: 20.6.3.28
Engine: MergeTree
OS: Ubuntu 18.04.3 LTS

Steps to reproduce:
```sql
CREATE TABLE table1(
	id int,
	price Nullable(Int32)
)
ENGINE = MergeTree()
PARTITION BY id
ORDER BY (id);
INSERT INTO table1 (id, price) VALUES (1, 100);
ALTER TABLE table1  update price = 150 where id=1;
SELECT * FROM table1;
```
We expect the price to be `150`, but it's `93148480`:

```
┌─id─┬────price─┐
│  1 │ 93148480 │
└────┴──────────┘
```
Using `Decimal(9,2)` field instead of `Int32` would set the value  `932342.88` always. It seems there's a fixed value for each data type.

If we don't use such a `where` clause, it works correctly:
```sql
ALTER TABLE db1.table1  update price = 150 where 1=1;
┌─id─┬─price─┐
│  1 │   150 │
└────┴───────┘
```
{
        const bool isnan_a = std::isnan(a);
        const bool isnan_b = std::isnan(b);
        if (unlikely(isnan_a || isnan_b))
        {
            if (isnan_a && isnan_b)
                return 0;
            return isnan_a
                ? nan_direction_hint
                : -nan_direction_hint;
        }
        return (T(0) < (a - b)) - ((a - b) < T(0));
    }
};
template <class U> struct CompareHelper<Float32, U> : public FloatCompareHelper<Float32> {};
template <class U> struct CompareHelper<Float64, U> : public FloatCompareHelper<Float64> {};
/** A template for columns that use a simple array to store.
 */
template <typename T>
class ColumnVector final : public COWHelper<ColumnVectorHelper, ColumnVector<T>>