* Remove unnecessary entry_height from BankInfo
* Refactor process_blocktree to support process_blocktree_from_root
* Refactor to process blocktree after loading from snapshot
* On restart make sure bank_forks contains all the banks between the root and the tip of each fork, not just the head of each fork
* Account for 1 tick_per_slot in bank 0 so that blockhash of bank0 matches the tick