Assume that the test database exists

The tests should not drop the test database and then recreate it. This
adds an unnecessary burden on replication which will cause false positives
when replication is not fast enough.

maxscale-system-test/short_sessions.cpp

@@ -24,8 +24,6 @@ int main(int argc, char *argv[])
     test.repl->connect();
 
     MYSQL *conn = test.open_rwsplit_connection();
-    execute_query(conn, "DROP DATABASE IF EXISTS test;");
-    execute_query(conn, "CREATE DATABASE test;");
     execute_query(conn, "USE test;");
     create_t1(conn);
     mysql_close(conn);