Cleanup some mostly unused xenial jobs

One job is an ancient job for running Zuul unittests and the other is
only necessary if we're going to continue supporting Xenial nodes (which
we're not). Delete them.

Change-Id: Ib4d015798cfd1a2fd7931ccd38d570cd30355040

zuul.d/jobs.yaml

@@ -3,17 +3,6 @@
 #    https://opendev.org/openstack/project-config
 #    https://opendev.org/zuul/zuul-jobs
 
-- job:
-    name: tox-py35-on-zuul
-    parent: tox-py35
-    nodeset: ubuntu-xenial
-    description: |
-      Run zuul's py35 unittests on patches to zuul-jobs.
-    vars:
-      zuul_work_dir: src/opendev.org/zuul/zuul
-    required-projects:
-      - zuul/zuul
-
 - job:
     name: openstack-tox
     abstract: true
@@ -1481,13 +1470,8 @@
       - ^roles/prepare-zanata-client/.*
       - ^tests/.*
 
-# NOTE(ianw): This test restricted to the two node types these roles
+# NOTE(ianw): This test restricted to the node type these roles
 # run on in the gate.
-- job:
-    name: openstack-infra-extra-integration-xenial
-    parent: openstack-infra-extra-integration
-    nodeset: ubuntu-xenial
-
 - job:
     name: openstack-infra-extra-integration-bionic
     parent: openstack-infra-extra-integration

zuul.d/project.yaml

@@ -13,7 +13,6 @@
         - openafs-rpm-package-build-centos-8-stream-arm64
         - openafs-rpm-package-build-centos-9-stream-x86
         - openafs-rpm-package-build-centos-9-stream-arm64
-        - openstack-infra-extra-integration-xenial
         - openstack-infra-extra-integration-bionic
         - openstack-zuul-jobs-linters
         - build-wheel-cache-centos-8-stream: