Revert "Update nested-virt testing for the 2023.1 cycle"

This reverts commit f0d7d3ee057a8a95c48cf8c343474fe96233bb5d.

Reason for revert: vexxhost node provider is having issues with
jammy nodes as guest vms are not booting on 40% of scenario jobs and leading to failures as mentioned in #1999249.
Also guest vms started to take too much memory(1GiB+) in jammy[1] so it's not possible to run multiple guests vms together like we do in our tests. Using swap makes vm boot too slow(200+ sec) on those systems and without swap it just ooom-kills.

Until vexxhost node provider supports jammy hosts or we are
able to run our tests in non nested-virt providers[2] reverting
this switch, may need some job splits or ideally fixing [1] in nova
or by some global libvirt/qemu config[3].

[1] https://bugs.launchpad.net/nova/+bug/1949606
[2] https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/867934
[3] https://listman.redhat.com/archives/libvirt-users/2022-December/013844.html

Change-Id: Iad827b4bd04534bf19e189cebb2839ebe4d3837e
Related-Bug: #1999249
diff --git a/zuul.d/base-nested-switch.yaml b/zuul.d/base-nested-switch.yaml
index 959b5ed..dcc0175 100644
--- a/zuul.d/base-nested-switch.yaml
+++ b/zuul.d/base-nested-switch.yaml
@@ -8,38 +8,12 @@
         nodes:
           - controller
 
-- nodeset:
-    name: neutron-nested-virt-ubuntu-jammy
-    nodes:
-      - name: controller
-        label: nested-virt-ubuntu-jammy
-    groups:
-      - name: tempest
-        nodes:
-          - controller
-
-# Base nested switch job for 2023.1 and later
+# Base nested switch job for non EM releases
 - job:
     name: neutron-tempest-plugin-base-nested-switch
     parent: neutron-tempest-plugin-base
     abstract: true
-    branches: ^(?!stable/(queens|rocky|stein|train|ussuri|victoria|wallaby|xena|yoga|zed)).*$
-    # Comment nodeset and vars to switch back to non nested nodes
-    nodeset: neutron-nested-virt-ubuntu-jammy
-    vars:
-      devstack_localrc:
-        LIBVIRT_TYPE: kvm
-        LIBVIRT_CPU_MODE: host-passthrough
-        CIRROS_VERSION: 0.5.2
-        DEFAULT_IMAGE_NAME: cirros-0.5.2-x86_64-disk
-        DEFAULT_IMAGE_FILE_NAME: cirros-0.5.2-x86_64-disk.img
-
-# Base nested switch job for victoria through zed
-- job:
-    name: neutron-tempest-plugin-base-nested-switch
-    parent: neutron-tempest-plugin-base
-    abstract: true
-    branches: ^stable/(victoria|wallaby|xena|yoga|zed)$
+    branches: ^(?!stable/(queens|rocky|stein|train|ussuri)).*$
     # Comment nodeset and vars to switch back to non nested nodes
     nodeset: neutron-nested-virt-ubuntu-focal
     vars:
@@ -55,4 +29,4 @@
     name: neutron-tempest-plugin-scenario-nested-switch
     parent: neutron-tempest-plugin-base
     abstract: true
-    branches: ^stable/(queens|rocky|stein|train|ussuri)$
+    branches: ^(stable/(queens|rocky|stein|train|ussuri)).*$