Sort cloud regions in a stable way

* All comes first
* Then US regions
* Then all other regions alphabetically

awx/main/tests/unit/utils/test_common.py

@@ -174,3 +174,11 @@ def test_get_custom_venv_choices():
     with TemporaryDirectory(dir=settings.BASE_VENV_PATH) as temp_dir:
         os.makedirs(os.path.join(temp_dir, 'bin', 'activate'))
         assert common.get_custom_venv_choices() == [os.path.join(temp_dir, '')]
+
+
+def test_region_sorting():
+    s = [('Huey', 'China1'),
+         ('Dewey', 'UK1'),
+         ('Lewie', 'US1'),
+         ('All', 'All')]
+    assert [x[1] for x in sorted(s, key=common.region_sorting)] == ['All', 'US1', 'China1', 'UK1']