* a dedicated test for wsrep_retry_autocommit
* some galera_toi_* tests were only passing because wsrep_retry_autocommit
  was in effect. The tests were changed to do not use autocommit
* higher timeout values in galera_2nodes.cnf , galera_3nodes.cnf

# Conflicts:
#	mysql-test/suite/galera/galera_2nodes.cnf
#	mysql-test/suite/galera/r/galera_defaults.result
#	mysql-test/suite/galera_3nodes/galera_3nodes.cnf