added check_length optimization for I_S_NAME comparison


sql/event_data_objects.cc:
  added check_length optimization for I_S_NAME comparison
sql/events.cc:
  added check_length optimization for I_S_NAME comparison
sql/mysql_priv.h:
  added check_length optimization for I_S_NAME comparison
sql/repl_failsafe.cc:
  added check_length optimization for I_S_NAME comparison
sql/sql_db.cc:
  added check_length optimization for I_S_NAME comparison
sql/sql_parse.cc:
  added check_length optimization for I_S_NAME comparison
sql/sql_show.cc:
  added check_length optimization for I_S_NAME comparison
sql/sql_view.cc:
  added check_length optimization for I_S_NAME comparison
sql/table.cc:
  added check_length optimization for I_S_NAME comparison