Move unit test compat code out of lib/ansible/. (#46996)

* Move ansible.compat.tests to test/units/compat/.
* Fix unit test references to ansible.compat.tests.
* Move builtins compat to separate file.
* Fix classification of test/units/compat/ dir.

test/units/modules/network/cloudvision/test_cv_server_provision.py

@@ -14,8 +14,8 @@
 # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 #
 
-from ansible.compat.tests import unittest
-from ansible.compat.tests.mock import patch, Mock
+from units.compat import unittest
+from units.compat.mock import patch, Mock
 import sys
 sys.modules['cvprac'] = Mock()
 sys.modules['cvprac.cvp_client'] = Mock()