[SECURITY] Added a `teardown` section to the integration test for roles

Currently, the REST tests for security (and possibly others) don't clean up the environment
after they have run, eg. they don't delete the users and roles they create. This leads to
test failures, because in a subsequent run, a user or role already exists, so eg. a test
like `match: { role: { created: true } }` fails.

This patch adds a `teardown` section to the test, with `do` actions which are to be
executed _after_ the test runs.

This patch assumes that REST tests runners for all languages support the `teardown` directive
in a xUnimt nomenclature -- similarly to the `setup` directive, which they already support.

Original commit: elastic/x-pack-elasticsearch@70d0ff4ee9

elasticsearch/x-pack/security/src/test/resources/rest-api-spec/test/roles/11_idx_arrays.yaml

@@ -3,9 +3,28 @@
   - skip:
       features: headers
 
-  - do:
+  - setup:
-      cluster.health:
+      - do:
-          wait_for_status: yellow
+          cluster.health:
+            wait_for_status: yellow
+
+  - teardown:
+      - do:
+          xpack.security.delete_role:
+            name: "admin_role2"
+            ignore: 404
+
+      - do:
+          xpack.security.delete_user:
+            username: "joe"
+            ignore: 404
+
+      - do:
+          delete:
+            index: foo
+            type: doc
+            id: 1
+            ignore: 404
 
   - do:
       xpack.security.put_role:
@@ -50,7 +69,6 @@
   - match: { _index: foo }
   - match: { _type: doc }
   - match: { _id: "1"}
-  - match: { _version: 1}
   - match: { _source: { foo: bar }}
 
 # test that the role works on the cluster level