core, eth, trie: reuse trie journals in all our code

miner/worker.go

@@ -361,7 +361,7 @@ func (self *worker) push(work *Work) {
 
 // makeCurrent creates a new environment for the current cycle.
 func (self *worker) makeCurrent(parent *types.Block, header *types.Header) error {
-	state, err := state.New(parent.Root(), self.eth.ChainDb())
+	state, err := self.chain.StateAt(parent.Root())
 	if err != nil {
 		return err
 	}