BUG#18447874: WRONG RESULT COMING FROM SEMI-JOIN
BUG#18223655: ASSERTION FAILED: (INT)IDX >= 0 && IDX < PARENT_JOIN->TABLES
If the left-hand expression(LHE) of IN predicate is a scalar subquery, E.g
select  1 from `b`  where (select 1 from  d ) in (select `d` from `c`).
In current version, during transforming In-predicate into semi-join,
the select list of LHE and RHE will be extracted to construct a new equivalent
expression as the where_cond to be added to Outer-query. As for the example,
IN-predicate (select 1 from  d ) in (select `d` from `c`) will make a new
equal-condition like 1='d'. However, such a transformation is correct only if
table 'd' has one row. If it has an empty resultset, such a transformation is
incorrect. Moreover, by executing the scalar query to see whether the resultset
is empty or not is not allowed during resolve.

Actually, scalar query is parsed into an Item_cache object So in current patch,
the where_cond will be constructed as the followings, Item_cache<(select 1 from
d )> = Item_row('d'). During execution, Item_cache will be filled by executing
the scalar query, which will make the query get the right result.