upgrading node for voltha-unit-tests as many times it runs out of memory

Change-Id: I25c0b66a9c9baa23879e4f56e0228bc106d8751f
diff --git a/jjb/voltha-unit-test.yaml b/jjb/voltha-unit-test.yaml
index 3913d5c..22b4456 100644
--- a/jjb/voltha-unit-test.yaml
+++ b/jjb/voltha-unit-test.yaml
@@ -35,7 +35,7 @@
           choosing-strategy: gerrit
           jenkins-ssh-credential: '{jenkins-ssh-credential}'
 
-    node: 'ubuntu16.04-basebuild-1c-2g'
+    node: 'ubuntu16.04-basebuild-4c-8g'
     project-type: freestyle
     concurrent: true