Improve command package isolation.

pkg/commands/build/testdata/testcase-variable-ref/in/package/cronjob.yaml

@@ -0,0 +1,21 @@
+apiVersion: batch/v1beta1
+kind: CronJob
+metadata:
+  name: cronjob-example
+spec:
+  schedule: "*/1 * * * *"
+  concurrencyPolicy: Forbid
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: cronjob-example
+            image: cockroachdb/cockroach:v1.1.5
+            command:
+            - echo
+            - "$(CDB_STATEFULSET_NAME)"
+            - "$(TEST_CONFIG_MAP)"
+            env:
+              - name: CDB_PUBLIC_SVC
+                value: "$(CDB_PUBLIC_SVC)"