[SCB-2385]fix IsolationDiscoveryFilter create many temporary objects (#2731)

diff --git a/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java b/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java
index c4b99d3..7919c1d 100644
--- a/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java
+++ b/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java
@@ -115,7 +115,6 @@
     } else {
       child.data(filteredServers);
     }
-    parent.child("filterred", child);
     return child;
   }