Ensure pending block is finalized and assembled

Before introducing this change gas estimations against the pending block
would sometimes be lower than they should be.

miner/worker.go

@@ -315,6 +315,13 @@ func (w *worker) constructPendingStateBlock(ctx context.Context, txsCh chan core
 	}
 	w.updatePendingBlock(b)
 
+	_, err = b.finalizeAndAssemble(w)
+	if err != nil {
+		log.Error("Failed to finalize and assemble the block", "err", err)
+		return
+	}
+	w.updatePendingBlock(b)
+
 	w.mu.RLock()
 	txFeeRecipient := w.txFeeRecipient
 	if !w.chainConfig.IsDonut(b.header.Number) && w.txFeeRecipient != w.validator {
@@ -347,6 +354,11 @@ func (w *worker) constructPendingStateBlock(ctx context.Context, txsCh chan core
 				// Only update the snapshot if any new transactons were added
 				// to the pending block
 				if tcount != b.tcount {
+					_, err = b.finalizeAndAssemble(w)
+					if err != nil {
+						log.Error("Failed to finalize and assemble the block", "err", err)
+						return
+					}
 					w.updatePendingBlock(b)
 				}
 			}