Incorrectly Set Nullability to False in FilterExec

When FilterExec contains isNotNull, which could be inferred and pushed down or users specified, we convert the nullability of the involved columns if the top-layer expression is null-intolerant. However, this is not true, if the top-layer expression is not a leaf expression, it could still tolerate the null when it has null-tolerant child expression.

For example, cast(coalesce(a#5, a#15) as double). Although cast is a null-intolerant expression, but obviously coalesce is a null-tolerant.

When the nullability is wrong, we could generate incorrect results in different cases.