I have 2 hosts: server1 (master) and server2(slave). By mistake I've created and dropped a database "test" on server2(slave). If the cluster will switch the master to server2, will there be any issues?
That depends. If the test database on the Master was never in use, then the slave won't care. As long as the slave is not a master to another server, then you are OK.
If the slave has binary logging enabled, the database will just get created and dropped and a record of it would be in the binary logs of the slave.
Besides a test database would not be in use in Production.