MDEV-17804: Galera tests cause mysql_socket.h:738: inline_mysql_socket_send:...

MDEV-17804: Galera tests cause mysql_socket.h:738: inline_mysql_socket_send: Assertion `mysql_socket.fd != -1' failed.

Do not do end of statement logic if thd is already killed as
socket is already closed.

mysql-test/suite/galera/r/galera_ist_mysqldump,debug.rdiff

---- r/galera_ist_mysqldump.result	2018-09-11 12:38:42.027479411 +0300
-+++ r/galera_ist_mysqldump.reject	2018-09-17 10:28:44.483441364 +0300
-@@ -180,6 +180,103 @@
+--- r/galera_ist_mysqldump.result	2018-11-22 14:25:28.551554055 +0200
++++ r/galera_ist_mysqldump.reject	2018-11-22 15:46:33.119441931 +0200
+@@ -200,6 +200,114 @@
  DROP TABLE t1;
  COMMIT;
  SET AUTOCOMMIT=ON;
 +Performing State Transfer on a server that has been killed and restarted
 +while a DDL was in progress on it
++connection node_1;
 +CREATE TABLE t1 (f1 CHAR(255)) ENGINE=InnoDB;
 +SET AUTOCOMMIT=OFF;
 +START TRANSACTION;
@@ -14,6 +15,7 @@
 +INSERT INTO t1 VALUES ('node1_committed_before');
 +INSERT INTO t1 VALUES ('node1_committed_before');
 +INSERT INTO t1 VALUES ('node1_committed_before');
++connection node_2;
 +START TRANSACTION;
 +INSERT INTO t1 VALUES ('node2_committed_before');
 +INSERT INTO t1 VALUES ('node2_committed_before');
@@ -22,9 +24,12 @@
 +INSERT INTO t1 VALUES ('node2_committed_before');
 +COMMIT;
 +SET GLOBAL debug_dbug = 'd,sync.alter_opened_table';
++connection node_1;
 +ALTER TABLE t1 ADD COLUMN f2 INTEGER;
++connection node_2;
 +SET wsrep_sync_wait = 0;
 +Killing server ...
++connection node_1;
 +SET AUTOCOMMIT=OFF;
 +START TRANSACTION;
 +INSERT INTO t1 (f1) VALUES ('node1_committed_during');
@@ -39,6 +44,7 @@
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_committed_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_committed_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_committed_after');
++connect node_1a_galera_st_kill_slave_ddl, 127.0.0.1, root, , test, $NODE_MYPORT_1;
 +SET AUTOCOMMIT=OFF;
 +START TRANSACTION;
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
@@ -46,7 +52,9 @@
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
++connection node_2;
 +Performing --wsrep-recover ...
++connection node_2;
 +Starting server ...
 +Using --wsrep-start-position when starting mysqld ...
 +SET AUTOCOMMIT=OFF;
@@ -57,6 +65,7 @@
 +INSERT INTO t1 (f1) VALUES ('node2_committed_after');
 +INSERT INTO t1 (f1) VALUES ('node2_committed_after');
 +COMMIT;
++connection node_1;
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_committed_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_committed_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_committed_after');
@@ -71,6 +80,7 @@
 +INSERT INTO t1 (f1) VALUES ('node1_committed_after');
 +INSERT INTO t1 (f1) VALUES ('node1_committed_after');
 +COMMIT;
++connection node_1a_galera_st_kill_slave_ddl;
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
 +INSERT INTO t1 (f1) VALUES ('node1_to_be_rollbacked_after');
@@ -88,6 +98,7 @@
 +1
 +COMMIT;
 +SET AUTOCOMMIT=ON;
++connection node_1;
 +SELECT COUNT(*) = 2 FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 't1';
 +COUNT(*) = 2
 +1
@@ -101,6 +112,6 @@
 +COMMIT;
 +SET AUTOCOMMIT=ON;
 +SET GLOBAL debug_dbug = $debug_orig;
+ connection node_1;
  CALL mtr.add_suppression("Slave SQL: Error 'The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement' on query");
  DROP USER sst;
- CALL mtr.add_suppression("Slave SQL: Error 'The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement' on query");

sql/sql_parse.cc

@@ -1940,7 +1940,8 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     /* wsrep BF abort in query exec phase */
     mysql_mutex_lock(&thd->LOCK_thd_data);
     do_end_of_statement= thd->wsrep_conflict_state != REPLAYING &&
-                         thd->wsrep_conflict_state != RETRY_AUTOCOMMIT;
+                         thd->wsrep_conflict_state != RETRY_AUTOCOMMIT &&
+                         !thd->killed;
     mysql_mutex_unlock(&thd->LOCK_thd_data);
   }
   else