Describe the feature

The HashedPostStateAccountCursor and HashedPostStateStorageCursor currently use a combination of iterator over updated accounts/slots and a separate HashSet of cleared accounts/slots to act as an overlay over the underlying Cursor.

This could be made more efficient by removing the HashSet on each, and making the iterator into an iterator over an Option<Account> (for accounts) or U256 (for storages, U256::ZERO indicates deleted).

This change will require accompanying changes to HashedPostStateSorted.

A previous PR was already merged, #18479 , which performed essentially this exact change but for TrieUpdates. This PR can be used as a guide; the logic and necessary changes should be effectively the same, just the types are different.

Additional context

No response