Fixed type and testing of last_update type for innodb_table_stats

mysql-test/r/connect.result:
  Removed tables which are not created anymore
sql/item_sum.h:
  Fixed typo
sql/sql_base.cc:
  Don't update table and index statics for temporary tables
sql/sys_vars.cc:
  Merge
storage/innobase/dict/dict0stats.cc:
  Fixed type last_update to TIMESTAMP.