[TEST] Don't invoke RoutingNodes.assertShardStats() via asserts many times in tests, just once on each reroute call.

src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java

@@ -513,7 +513,6 @@ public class RoutingNodes implements Iterable<RoutingNode> {
         if (routingNode == null) {
             return null;
         }
-        assert assertShardStats(this);
         return new RoutingNodeIterator(routingNode);
     }
 

src/main/java/org/elasticsearch/cluster/routing/allocation/AllocationService.java

@@ -261,7 +261,6 @@ public class AllocationService extends AbstractComponent {
                 if (!moved) {
                     logger.debug("[{}][{}] can't move", shardRouting.index(), shardRouting.id());
                 } else {
-                    assert RoutingNodes.assertShardStats(allocation.routingNodes());
                     changed = true;
                 }
             }