CI: Use the debug stdout callback instead of manual debug

This display in a readable (by humans) way the result of most tasks, and
should be way more readable that what we have now, which is frequently a
bunch of unreadable json.

+ some small fixes (using delegated_to instead of when
  <control_plane_host>)

tests/testcases/020_check-pods-running.yml

@@ -19,10 +19,6 @@
   - name: Check kubectl output
     command: "{{ bin_dir }}/kubectl get pods --all-namespaces -owide"
     changed_when: false
-    register: get_pods
-
-  - debug:  # noqa name[missing]
-      msg: "{{ get_pods.stdout.split('\n') }}"
 
   - name: Check that all pods are running and ready
     command: "{{ bin_dir }}/kubectl get pods --all-namespaces --no-headers -o yaml"
@@ -35,13 +31,7 @@
     - '(run_pods_log.stdout | from_yaml)["items"] | map(attribute = "status.containerStatuses") | map("map", attribute = "ready") | map("min") | min'
     retries: 30
     delay: 10
-    failed_when: false
 
   - name: Check kubectl output
     command: "{{ bin_dir }}/kubectl get pods --all-namespaces -owide"
     changed_when: false
-    register: get_pods
-
-  - debug:  # noqa name[missing]
-      msg: "{{ get_pods.stdout.split('\n') }}"
-    failed_when: not run_pods_log is success