Bug #33931 assertion at write_ignored_events_info_to_relay_log if init_slave_thread() fails

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.

mysql-test/r/rpl_bug33931.result

@@ -0,0 +1,38 @@
+reset master;
+stop slave;
+reset slave;
+start slave;
+show slave status;
+Slave_IO_State	#
+Master_Host	127.0.0.1
+Master_User	root
+Master_Port	MASTER_PORT
+Connect_Retry	1
+Master_Log_File	
+Read_Master_Log_Pos	4
+Relay_Log_File	#
+Relay_Log_Pos	#
+Relay_Master_Log_File	
+Slave_IO_Running	No
+Slave_SQL_Running	No
+Replicate_Do_DB	
+Replicate_Ignore_DB	
+Replicate_Do_Table	
+Replicate_Ignore_Table	
+Replicate_Wild_Do_Table	
+Replicate_Wild_Ignore_Table	
+Last_Errno	0
+Last_Error	
+Skip_Counter	0
+Exec_Master_Log_Pos	0
+Relay_Log_Space	#
+Until_Condition	None
+Until_Log_File	
+Until_Log_Pos	0
+Master_SSL_Allowed	No
+Master_SSL_CA_File	
+Master_SSL_CA_Path	
+Master_SSL_Cert	
+Master_SSL_Cipher	
+Master_SSL_Key	
+Seconds_Behind_Master	#