Report single node clusters as non-ha (#11212)

* Report single node clusters as non-ha

* Move test file so we can make it use the database

* Update unit test to accomidate different node types

awx/main/tests/unit/test_ha.py

@@ -1,17 +0,0 @@
-# Copyright (c) 2016 Ansible, Inc.
-
-# Python
-from unittest import mock
-
-# AWX
-from awx.main.ha import is_ha_environment
-
-
-@mock.patch('awx.main.models.Instance.objects.count', lambda: 2)
-def test_multiple_instances():
-    assert is_ha_environment()
-
-
-@mock.patch('awx.main.models.Instance.objects.count', lambda: 1)
-def test_db_localhost():
-    assert is_ha_environment() is False