CI: cleanup '-scale' tests infra (#11535)

There is actually no test using this since ad6fecef,
so there is no reason to keep that infra in our tests scripts.

docs/developers/test_cases.md

 # Node Layouts
 
-There are six node layout types: `default`, `separate`, `ha`, `scale`, `all-in-one`, and `node-etcd-client`.
+There are five node layout types: `default`, `separate`, `ha`, `all-in-one`, and `node-etcd-client`.
 
 `default` is a non-HA two nodes setup with one separate `kube_node`
 and the `etcd` group merged with the `kube_control_plane`.
@@ -11,11 +11,6 @@ and the `etcd` group merged with the `kube_control_plane`.
 `ha` layout consists of two etcd nodes, two control planes and a single worker node,
 with role intersection.
 
-`scale` layout can be combined with above layouts (`ha-scale`, `separate-scale`). It includes 200 fake hosts
-in the Ansible inventory. This helps test TLS certificate generation at scale
-to prevent regressions and profile certain long-running tasks. These nodes are
-never actually deployed, but certificates are generated for them.
-
 `all-in-one` layout use a single node for with `kube_control_plane`, `etcd` and `kube_node` merged.
 
 `node-etcd-client` layout consists of a 4 nodes cluster, all of them in `kube_node`, first 3 in `etcd` and only one `kube_control_plane`.

tests/cloud_playbooks/roles/packet-ci/templates/inventory.j2

@@ -3,7 +3,7 @@
 instance-{{ loop.index }} ansible_host={{instance.stdout}}
 {% endfor %}
 
-{% if mode is defined and mode in ["separate", "separate-scale"] %}
+{% if mode == "separate" %}
 [kube_control_plane]
 instance-1
 
@@ -12,7 +12,7 @@ instance-2
 
 [etcd]
 instance-3
-{% elif mode is defined and mode in ["ha", "ha-scale"] %}
+{% elif mode == "ha" %}
 [kube_control_plane]
 instance-1
 instance-2
@@ -103,5 +103,3 @@ kube_control_plane
 calico_rr
 
 [calico_rr]
-
-[fake_hosts]

tests/cloud_playbooks/roles/packet-ci/vars/main.yml

 ---
 _vm_count_dict:
   separate: 3
-  separate-scale: 3
   ha: 3
-  ha-scale: 3
   ha-recover: 3
   ha-recover-noquorum: 3
   all-in-one: 1

tests/scripts/testcases_run.sh

@@ -54,7 +54,7 @@ run_playbook () {
 playbook=$1
 shift
 # We can set --limit here and still pass it as supplemental args because `--limit`  is a 'last one wins' option
-ansible-playbook --limit "all:!fake_hosts" \
+ansible-playbook \
      $ANSIBLE_LOG_LEVEL \
     -e @${CI_TEST_SETTING} \
     -e @${CI_TEST_REGISTRY_MIRROR} \
@@ -85,8 +85,8 @@ fi
 
 # Test control plane recovery
 if [ "${RECOVER_CONTROL_PLANE_TEST}" != "false" ]; then
-    run_playbook reset.yml --limit "${RECOVER_CONTROL_PLANE_TEST_GROUPS}:!fake_hosts" -e reset_confirmation=yes
-    run_playbook recover-control-plane.yml -e etcd_retries=10 --limit "etcd:kube_control_plane:!fake_hosts"
+    run_playbook reset.yml --limit "${RECOVER_CONTROL_PLANE_TEST_GROUPS}" -e reset_confirmation=yes
+    run_playbook recover-control-plane.yml -e etcd_retries=10 --limit "etcd:kube_control_plane"
 fi
 
 # Test collection build and install by installing our collection, emptying our repository, adding

tests/templates/fake_hosts.yml.j2

-ansible_default_ipv4:
-  address: 255.255.255.255
-ansible_hostname: "{{ '{{' }}inventory_hostname }}"