Post-merge fixes:

- Fix derived_view.test to work, and enable it
- Let subselect*.test do "DROP TABLE IF EXISTS" before they attempt to create the table.

sql/sql_select.cc

@@ -14793,6 +14793,7 @@ free_tmp_table(THD *thd, TABLE *entry)
 
   if (entry->file && entry->created)
   {
+    entry->file->ha_index_or_rnd_end();
     if (entry->db_stat)
       entry->file->ha_drop_table(entry->s->table_name.str);
     else