[Exec](RF) Support merge remote rf local first (#31067)

fe/fe-core/src/main/java/org/apache/doris/qe/Coordinator.java

@@ -2150,7 +2150,8 @@ public class Coordinator implements CoordInterface {
             }
 
             for (RuntimeFilterId rid : fragment.getBuilderRuntimeFilterIds()) {
-                ridToBuilderNum.merge(rid, params.instanceExecParams.size(), Integer::sum);
+                ridToBuilderNum.merge(rid,
+                        (int) params.instanceExecParams.stream().map(ins -> ins.host).distinct().count(), Integer::sum);
             }
         }
         // Use the uppermost fragment as a merged node, the uppermost fragment has one and only one instance