Fixed a valgrind problem.

The function setup_tables should handle table_list elements for
semijoin materialized tables in a special way when executing
a prepared statement for the second time.

sql/sql_base.cc

@@ -7829,10 +7829,17 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
     List_iterator_fast <TABLE_LIST> ti(select_lex->leaf_tables_exec);
     select_lex->leaf_tables.empty();
     while ((table_list= ti++))
+    {
+      if(table_list->jtbm_subselect)
+      {
+        table_list->jtbm_table_no= table_list->tablenr_exec;
+      }
+      else
       {
         table_list->table->tablenr= table_list->tablenr_exec;
         table_list->table->map= table_list->map_exec;
         table_list->table->pos_in_table_list= table_list;
+      }
       select_lex->leaf_tables.push_back(table_list);
     }
   }    

sql/sql_select.cc

@@ -826,6 +826,7 @@ inject_jtbm_conds(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
       
       //repeat of convert_subq_to_jtbm:
       table->table= hash_sj_engine->tmp_table;
+      table->table->pos_in_table_list= table;
 
       setup_table_map(table->table, table, table->jtbm_table_no);