Test system versioning against UDFs and nested selects

The purpose of the task is to add tests with expressions that can transform, say, during optimization.

Good example to start:

create or replace table t (x int) with system versioning engine=myisam;

insert into t values(1);

select * from t for system_time as of (select row_start from t where x in (select x from t));

The syntax is currently allowed. ... IN (SELECT ...) can be transformed to join.
There is also string constants which transforming and single select like (SELECT 1).