[NO ISSUE][ING] Allow external UDF to use runtime parallelism

- user model changes: no
- storage format changes: no
- interface changes:

Details:
1. Enable UDF in feed to use the runtime parallelism.
2. Fix the DefaultNodeDomain where the nodes should be mutliSet but not
list, for comparison purpose.

Change-Id: Ic3b54617be115f51b6a48b9a61581c26b5be8d9d
Reviewed-on: https://asterix-gerrit.ics.uci.edu/2398
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Contrib: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Michael Blow <mblow@apache.org>
diff --git a/hyracks-fullstack/algebricks/algebricks-core/pom.xml b/hyracks-fullstack/algebricks/algebricks-core/pom.xml
index 9f7d2bd..669988c 100644
--- a/hyracks-fullstack/algebricks/algebricks-core/pom.xml
+++ b/hyracks-fullstack/algebricks/algebricks-core/pom.xml
@@ -85,5 +85,9 @@
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-api</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-collections4</artifactId>
+    </dependency>
   </dependencies>
 </project>