Switch scenario jobs to nested-virt nodes

To avoid intermittent failures and job timeouts
in scenario jobs, move these jobs to nested virt nodes.

Only moving scenario jobs as those are mostly affected
by intermittent issues(SSH Tempest failures) and job
timeouts. Also nested virt nodes are provided only by a
few nodepool providers.

Also switching non-scenario jobs to use cirros uec
image to avoid kernel panic issue.

Initial tests were done with [2] and issues/improvements
are being tracked at [3].

[1] https://bugs.launchpad.net/nova/+bug/1939108
[2] https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/819590
[3] https://etherpad.opendev.org/p/neutron-ci-improvements

Related-Bug: #1952066
Related-Bug: #1953479
Change-Id: I2f78f9de1ad1dc8c34688951c6bb2d5648d5dc3f
diff --git a/zuul.d/master_jobs.yaml b/zuul.d/master_jobs.yaml
index 0139f8e..99d7b43 100644
--- a/zuul.d/master_jobs.yaml
+++ b/zuul.d/master_jobs.yaml
@@ -527,6 +527,8 @@
         NETWORK_API_EXTENSIONS: "{{ (network_api_extensions_common + network_api_extensions_dvr) | join(',') }}"
         PHYSICAL_NETWORK: default
         CIRROS_VERSION: 0.5.1
+        DEFAULT_IMAGE_NAME: cirros-0.5.1-x86_64-uec
+        DEFAULT_IMAGE_FILE_NAME: cirros-0.5.1-x86_64-uec.tar.gz
         IMAGE_URLS: https://cloud-images.ubuntu.com/minimal/releases/focal/release/ubuntu-20.04-minimal-cloudimg-amd64.img
         ADVANCED_IMAGE_NAME: ubuntu-20.04-minimal-cloudimg-amd64
         ADVANCED_INSTANCE_TYPE: ntp_image_256M