MDEV-15823: Test failure on galera.galera_var_slave_threads

Wait drop table to be replicated before continuing.

mysql-test/suite/galera/disabled.def

@@ -34,4 +34,3 @@ query_cache : MDEV-15805 Test failure on galera.query_cache
 galera.galera_gra_log : MDEV-15808 Test failure on galera.galera_gra_log
 galera.MW-44 : MDEV-15809 Test failure on galera.MW-44
 galera.galera_pc_ignore_sb : MDEV-15811 Test failure on galera_pc_ignore_sb
-galera.galera_var_slave_threads : MDEV-15785 Test failure on galera.galera_var_slave_threads

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

@@ -109,6 +109,8 @@ INSERT INTO t1 VALUES (DEFAULT);
 INSERT INTO t1 VALUES (DEFAULT);
 INSERT INTO t1 VALUES (DEFAULT);
 DROP TABLE t1;
+SELECT NAME FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE NAME LIKE 'test/t%';
+NAME
 SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND STATE LIKE '%wsrep aborter%';
 COUNT(*) = 1
 1

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

@@ -88,6 +88,13 @@ INSERT INTO t1 VALUES (DEFAULT);
 DROP TABLE t1;
 
 --connection node_2
+
+# Wait until above DDL is replicated
+--let $wait_condition = SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE NAME LIKE 'test/t%';
+--source include/wait_condition.inc
+
+SELECT NAME FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE NAME LIKE 'test/t%';
+
 #
 # make sure that we are left with exactly one applier thread before we leaving the test
 #