MDEV-14786 Server crashes in Item_cond::transform on 2nd execution of SP querying from a view

instead of skipping invalid items in setup_conds(),
don't pass them into a JOIN at all

(test case in versioning.select2)

sql/sql_base.cc

@@ -7997,10 +7997,6 @@ int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
   TABLE_LIST *derived= select_lex->master_unit()->derived;
   DBUG_ENTER("setup_conds");
 
-  /* Do not fix conditions for the derived tables that have been merged */
-  if (derived && derived->merged)
-    DBUG_RETURN(0);
-
   select_lex->is_item_list_lookup= 0;
 
   thd->mark_used_columns= MARK_COLUMNS_READ;

sql/sql_union.cc

@@ -645,6 +645,7 @@ bool st_select_lex_unit::prepare_join(THD *thd_arg, SELECT_LEX *sl,
                                       bool is_union_select)
 {
   DBUG_ENTER("st_select_lex_unit::prepare_join");
+  TABLE_LIST *derived= sl->master_unit()->derived;
   bool can_skip_order_by;
   sl->options|=  SELECT_NO_UNLOCK;
   JOIN *join= new JOIN(thd_arg, sl->item_list,
@@ -660,7 +661,7 @@ bool st_select_lex_unit::prepare_join(THD *thd_arg, SELECT_LEX *sl,
 
   saved_error= join->prepare(sl->table_list.first,
                              sl->with_wild,
-                             sl->where,
+                             (derived && derived->merged ? NULL : sl->where),
                              (can_skip_order_by ? 0 :
                               sl->order_list.elements) +
                              sl->group_list.elements,