core/state/snapshot, ethdb: track deletions more accurately (#22582)

* core/state/snapshot, ethdb: track deletions more accurately

* core/state/snapshot: don't reset the iterator, leveldb's screwy

* ethdb: don't mess with the insert batches for now

ethdb/memorydb/memorydb.go

@@ -211,7 +211,7 @@ func (b *batch) Put(key, value []byte) error {
 // Delete inserts the a key removal into the batch for later committing.
 func (b *batch) Delete(key []byte) error {
 	b.writes = append(b.writes, keyvalue{common.CopyBytes(key), nil, true})
-	b.size += 1
+	b.size += len(key)
 	return nil
 }