Now we should call open_and_lock_tables() even if table list is empty -
to cache stored routines used by query and open and lock tables required
for their execution.


sql/sql_insert.cc:
  Now we should call open_and_lock_tables() even if table list is empty -
  to cache stored routines used by query and open and lock tables required
  for their execution.
sql/sql_prepare.cc:
  Now we should call open_and_lock_tables() even if table list is empty -
  to cache stored routines used by query and open and lock tables required
  for their execution. Thus we have to move most of functionality from 
  select_like_statement_test() to separate function to be able to reuse it
  for multi-update processing (for which tables are open and locked in 
  mysql_multi_update_prepare() call).