Handle cleaning of zero-lamport accounts w.r.t. Incremental Snapshots (#18870)

* Handle cleaning zero-lamport accounts

Handle cleaning zero-lamport accounts in slots higher than the last full
snapshot slot.  This is part of the Incremental Snapshot work.

Fixes #18825

ledger/src/blockstore_processor.rs

@@ -1155,7 +1155,7 @@ fn load_frozen_forks(
                     // Must be called after `squash()`, so that AccountsDb knows what
                     // the roots are for the cache flushing in exhaustively_free_unused_resource().
                     // This could take few secs; so update last_free later
-                    new_root_bank.exhaustively_free_unused_resource();
+                    new_root_bank.exhaustively_free_unused_resource(None);
                     last_free = Instant::now();
                 }