core, trie: intermediate mempool between trie and database (#15857)

This commit reduces database I/O by not writing every state trie to disk.

miner/worker.go

@@ -309,7 +309,7 @@ func (self *worker) wait() {
 			for _, log := range work.state.Logs() {
 				log.BlockHash = block.Hash()
 			}
-			stat, err := self.chain.WriteBlockAndState(block, work.receipts, work.state)
+			stat, err := self.chain.WriteBlockWithState(block, work.receipts, work.state)
 			if err != nil {
 				log.Error("Failed writing block to chain", "err", err)
 				continue