Using Column Instead of AST to Store Scalar Subquery Results for Better Performance

Using column instead of AST to store scalar subquery results for better performance. Setting enable_scalar_subquery_optimization was added in 19.17 and it was enabled by default. It leads to errors like this during upgrade to 19.17.2 or 19.17.3 from previous versions. This setting was disabled by default in 19.17.4, to make possible upgrading from 19.16 and older versions without errors. #7392 (Amos Bird)