[hl][mysql] sys.db.Connection close function not work on linux.

class Main {
static function main() {

var cnx = sys.db.Mysql.connect({
host : "127.0.0.1",
port : 33826,
user : "test",
pass : "test",
database : "test"
});

var rs= cnx.request('select * from fa_customer');
trace(rs.length);

cnx.close();//work ok on windows.but fail on ubuntu 18.
}

}



**hxcpp** test ok