MDEV-23328 Server hang due to Galera lock conflict resolution

Use better error message when KILL fails even in case TOI
fails.

mysql-test/suite/galera/r/galera_to_error.result

@@ -15,10 +15,10 @@ Killing server ...
 connect node_1c, 127.0.0.1, root, , test, $NODE_MYPORT_1;
 connection node_1c;
 CREATE TABLE t1 (f1 INTEGER NOT NULL PRIMARY KEY) ENGINE=InnoDB;
-ERROR 40001: WSREP replication failed. Check your wsrep connection state and retry the query.
-ERROR 40001: WSREP replication failed. Check your wsrep connection state and retry the query.
+Got one of the listed errors
+Got one of the listed errors
 CREATE UNIQUE INDEX b2 ON t2(b);
-ERROR 08S01: WSREP has not yet prepared node for application use
+Got one of the listed errors
 connection node_1;
 disconnect node_1a;
 disconnect node_1b;

mysql-test/suite/galera/t/galera_to_error.test

@@ -34,16 +34,16 @@ BEGIN;
 
 --connect node_1c, 127.0.0.1, root, , test, $NODE_MYPORT_1
 --connection node_1c
---error ER_LOCK_DEADLOCK
+--error ER_LOCK_DEADLOCK,ER_UNKNOWN_COM_ERROR
 CREATE TABLE t1 (f1 INTEGER NOT NULL PRIMARY KEY) ENGINE=InnoDB;
 
 --disable_query_log
---error ER_LOCK_DEADLOCK
+--error ER_LOCK_DEADLOCK, ER_CANNOT_USER,ER_KILL_QUERY_DENIED_ERROR
 --eval KILL QUERY $k_thread;
 --enable_query_log
 
 # Reset the master and restart the slave so that post-test checks can run
---error 1047
+--error ER_LOCK_DEADLOCK,ER_UNKNOWN_COM_ERROR
 CREATE UNIQUE INDEX b2 ON t2(b);
 
 --connection node_1

sql/sql_parse.cc

@@ -9093,7 +9093,9 @@ void sql_kill(THD *thd, longlong id, killed_state state, killed_type type)
 #ifdef WITH_WSREP
   return;
  wsrep_error_label:
-  my_error(ER_CANNOT_USER, MYF(0), " ");
+  error= (type == KILL_TYPE_QUERY ? ER_KILL_QUERY_DENIED_ERROR :
+                                    ER_KILL_DENIED_ERROR);
+  my_error(error, MYF(0), id);
 #endif /* WITH_WSREP */
 }
 
@@ -9128,7 +9130,7 @@ void sql_kill_user(THD *thd, LEX_USER *user, killed_state state)
 #ifdef WITH_WSREP
   return;
  wsrep_error_label:
-  my_error(ER_CANNOT_USER, MYF(0), " ");
+  my_error(ER_CANNOT_USER, MYF(0), user ? user->user.str : "NULL");
 #endif /* WITH_WSREP */
 }