message: Correctly consider NULL values in obsolete filter removal
diff: @@ -232,8 +232,8 @@ unique_ptr<LogicalOperator> ObsoleteFilterRewriter::Rewrite(unique_ptr<LogicalOp
  if (child->type == ExpressionType::VALUE_CONSTANT) {
  auto &constant = (ConstantExpression &)*child;
  auto constant_value = constant.value.CastAs(TypeId::BOOLEAN);
  - if (!constant_value.value_.boolean) {
  - // FALSE, we can prune entire filter
  + if (constant_value.is_null || !constant_value.value_.boolean) {
  + // FALSE or NULL, we can prune entire filter
  prune_filter = true;
  break;
  } else {
  