* Adds get_sysvar_with_account_check2 for ABIv2. * Replaces get_signers() and get_sysvar_with_account_check() in system_instruction_processor. * Replaces KeyedAccount by BorrowedAccount in nonce_keyed_account.
* Adds get_sysvar_with_account_check2 for ABIv2. * Replaces get_signers() and get_sysvar_with_account_check() in system_instruction_processor. * Replaces KeyedAccount by BorrowedAccount in nonce_keyed_account.