BUG#952372: Server crashes on 2nd execution of PS in find_field_in_tables with semijoin+materialization
- The problem was that convert_subq_to_jtbm() attached the semi-join
  TABLE_LIST object into the wrong list: they used to attach it to the 
  end of parent_lex->leaf_tables.head()->next_local->...->next_local.
  This was apparently inccorect, as one can construct an example where 
  JTBM nest is attached to a table that is inside some mergeable VIEW, which
  breaks (causes crash) for name resolution on the subsequent statement
  re-execution.
- Solution: Attach to the "right" list. The "wording" was copied from
  st_select_lex::handle_derived.