Lotto Fix bug

1. subList doesn't copy list, so we need to pass sublist to constructor
2. Synchronized issue comes from using iterator in getHitCountBy. To
avoid this,
- 1) use stand for instead enhanced for, but this will cause not
covering all lottos generated after the time for loop starts.
- 2) CopyOnWriteList : this causes performance off.
- 3) use synchronize statement (not tried yet)