run XOS unit tests on a more substantial executor

Change-Id: I83c6c03d334be856c305f18c5791e16537af600d
diff --git a/jjb/verify/xos.yaml b/jjb/verify/xos.yaml
index e4d104f..3309d6c 100644
--- a/jjb/verify/xos.yaml
+++ b/jjb/verify/xos.yaml
@@ -33,6 +33,7 @@
           build-timeout: 45
       - 'python-unit-test':
           build-timeout: 45
+          build-node: 'ubuntu16.04-basebuild-2c-4g'
       - 'synchronizer-update'
       - 'api-test':
           pipeline_script: 'all-xos-api-test-helm.groovy'