remove reduant exchange exclusion (tronprotocol#6539)

Author: 317787106

framework/src/main/java/org/tron/core/db/Manager.java

@@ -881,11 +881,6 @@ public boolean pushTransaction(final TransactionCapsule trx)
       throw new ContractValidateException("ExchangeTransactionContract is rejected");
     }
 
-    if (isExchangeTransaction(trx.getInstance())) {
-      throw new ContractValidateException("ExchangeTransactionContract is rejected");
-    }
-
-
     pushTransactionQueue.add(trx);
     Metrics.gaugeInc(MetricKeys.Gauge.MANAGER_QUEUE, 1,
         MetricLabels.Gauge.QUEUE_QUEUED);