MDEV-27977 : galera.galera_UK_conflict fails with wrong result

Add wait_condition so that all rows expected are really
replicated before we check it.

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

@@ -144,7 +144,6 @@ SET debug_sync='RESET';
 connection node_1;
 SET GLOBAL wsrep_slave_threads = DEFAULT;
 connection node_2;
-SET SESSION wsrep_sync_wait=15;
 SELECT * FROM t1;
 f1	f2	f3
 1	1	0

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

@@ -140,6 +140,14 @@ SELECT * FROM t1;
 # original state in node 1
 INSERT INTO t1 VALUES (7,7,7);
 INSERT INTO t1 VALUES (8,8,8);
+SELECT COUNT(*) FROM t1;
+SELECT * FROM t1;
+
+--connection node_1
+--let $wait_condition = SELECT COUNT(*) = 7 FROM t1
+--source include/wait_condition.inc
+SELECT COUNT(*) FROM t1;
+SELECT * FROM t1;
 
 DROP TABLE t1;
 
@@ -268,7 +276,6 @@ SET debug_sync='RESET';
 SET GLOBAL wsrep_slave_threads = DEFAULT;
 
 --connection node_2
-SET SESSION wsrep_sync_wait=15;
 SELECT * FROM t1;
 
 # replicate some transactions, so that wsrep slave thread count can reach
@@ -276,4 +283,13 @@ SELECT * FROM t1;
 INSERT INTO t1 VALUES (7,7,7);
 INSERT INTO t1 VALUES (8,8,8);
 
+SELECT COUNT(*) FROM t1;
+SELECT * FROM t1;
+
+--connection node_1
+--let $wait_condition = SELECT COUNT(*) = 7 FROM t1
+--source include/wait_condition.inc
+SELECT COUNT(*) FROM t1;
+SELECT * FROM t1;
+
 DROP TABLE t1;