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/packaging/os/conftest.py

@@ -1,4 +1,4 @@
-from ansible.compat.tests.mock import patch
+from units.compat.mock import patch
 from ansible.module_utils.six.moves import xmlrpc_client
 
 import pytest

test/units/modules/packaging/os/test_apk.py

@@ -1,5 +1,5 @@
-from ansible.compat.tests import mock
-from ansible.compat.tests import unittest
+from units.compat import mock
+from units.compat import unittest
 
 from ansible.modules.packaging.os import apk
 

test/units/modules/packaging/os/test_apt.py

@@ -2,8 +2,8 @@ import collections
 import os
 import sys
 
-from ansible.compat.tests import mock
-from ansible.compat.tests import unittest
+from units.compat import mock
+from units.compat import unittest
 
 try:
     from ansible.modules.packaging.os.apt import (

test/units/modules/packaging/os/test_rhn_register.py

@@ -2,7 +2,7 @@ import contextlib
 import json
 import os
 
-from ansible.compat.tests.mock import mock_open
+from units.compat.mock import mock_open
 from ansible.module_utils import basic
 from ansible.module_utils._text import to_native
 import ansible.module_utils.six

test/units/modules/packaging/os/test_yum.py

@@ -1,6 +1,6 @@
 
 # -*- coding: utf-8 -*-
-from ansible.compat.tests import unittest
+from units.compat import unittest
 
 from ansible.modules.packaging.os.yum import YumModule