miner/worker: skip resubmit logic in Consortium

Currently, after 3 seconds, worker tries to create another block, optimistically
thinks that it can get more transactions and earns more fee as a result.
However, this causes overhead to the main block creating flow, so skip this
logic in Consortium.

miner/worker.go

@@ -450,7 +450,8 @@ func (w *worker) newWorkLoop(recommit time.Duration) {
 		case <-timer.C:
 			// If mining is running resubmit a new work cycle periodically to pull in
 			// higher priced transactions. Disable this overhead for pending blocks.
-			if w.isRunning() && (w.chainConfig.Clique == nil || w.chainConfig.Clique.Period > 0) {
+			if w.isRunning() &&
+				(w.chainConfig.Consortium == nil || w.chainConfig.Clique == nil || w.chainConfig.Clique.Period > 0) {
 				// Short circuit if no new transaction arrives.
 				if atomic.LoadInt32(&w.newTxs) == 0 {
 					timer.Reset(recommit)