and
bug#33932  assertion at handle_slave_sql if init_slave_thread() fails

the asserts were caused by 
  bug33931: having thd deleted at time of executing err: code plus
            a missed initialization;
  bug33932: initialization of slave_is_running member was missed;

fixed with relocating mi members initialization and removing delete thd
It is safe to do as deletion happens later explicitly in the caller of
init_slave_thread().

Todo: at merging the test is better to be moved into suite/bugs for 5.x (when x>0).


sql/slave.cc:
  adding the bugs simulating code;
  relocating some assignments to satisfy the asserts;
mysql-test/r/rpl_bug33931.result:
  the new result file
mysql-test/t/rpl_bug33931-slave.opt:
  option to spark the simulation code
mysql-test/t/rpl_bug33931.test:
  tests check that slave does not crash as before.
  Slave threads must be in NO running state in the end.