deisolation of RC handling of virtual operations

The change with power down introduces small change in amount of RC mana in some cases. Previously code in visitor always regenerated RC mana for target account, now it only happens when target is receiving vests (which only happens for vesting route with vesting enabled - a relatively rare occurrence). It means there is less truncations for some accounts which in turn leads to them having slightly more RC mana (typically 1 point for each superfluous regeneration eliminated). RC stamps introduced in !1138 (merged) are designed precisely to catch such subtle differences that would most likely stay unnoticed otherwise.

There is also fix for content of hardfork_hive_operation vop in AH - the balances were previously empty (because AH was storing them before they were filled). Now the vop is emitted at the end.