* Add feature gate
* Add helper fn
* Require split destination to be rent-exempt if it is active
* Update cli to prefund split accounts
* cli: require rent param with sign-only
* Update tokens to prefund split accounts
* Update split tests with sysvar accounts
* Fix test_split_to_account_with_rent_exempt_reserve
* Fix test_staked_split_destination_minimum_balance
* Fix test_split_more_than_staked
* Fix test_split_minimum_stake_delegation and remove misleading StakeState::Initialized case
* Fix test_split_from_larger_sized_account
* Add test for pre-/post-activation behavior splitting some or all of stake account
* Assert active stake
* Fix runtime test
* Ignore stake-pool downstream
* Review comments
* Feature gate sysvar reads