we do not increment rli->group_master_log_pos if we are just after a SET ONE_SHOT (it's not a standalone event)


mysql-test/r/rpl_charset.result:
  testing interruption of slave SQL thread between SET CHARACTER_SET_SERVER... and the companion INSERT.
mysql-test/t/rpl_charset.test:
  testing interruption of slave SQL thread between SET CHARACTER_SET_SERVER... and the companion INSERT.
sql/log_event.cc:
  we do not increment rli->group_master_log_pos if we are just after a SET
  ONE_SHOT, because SET ONE_SHOT should not be separated from its following
  updating query.