##### SUMMARY
add_host will return 'changed' for every invocation, it does not matter if the host already existed and no changes were actually made to inventory

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
add_host
##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.7, 2.8, 2.9, 2.10
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
all

##### STEPS TO REPRODUCE

Simplest example, but also happens when specifying variables and/or groups

test.yml
```yaml
- hosts: localhost
  gather_facts: false
  tasks:
    - add_host: name=testhost
```
test_inv.ini
```ini
testhost
```
run:
``` ansible-playbook -i test_inv.ini test.yml```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
```
 _________________
< TASK [add_host] >
 -----------------
       \   ,__,
        \  (oo)____
           (__)    )\
              ||--|| *

OK: [localhost]
```

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
 _________________
< TASK [add_host] >
 -----------------
       \   ,__,
        \  (oo)____
           (__)    )\
              ||--|| *

changed: [localhost]
```

if notified_hosts is None:
            notified_hosts = handler.notified_hosts[:]
        
        failed_hosts = self._filter_notified_failed_hosts(iterator, notified_hosts)
        notified_hosts = self._filter_notified_hosts(notified_hosts)
        notified_hosts += failed_hosts
        if len(notified_hosts) > 0:
            saved_name = handler.name
            handler.name = handler_name
            self._tqm.send_callback('v2_playbook_on_handler_task_start', handler)
            handler.name = saved_name
        bypass_host_loop = False
        try:
            action = plugin_loader.action_loader.get(handler.action, class_only=True)
            if getattr(action, 'BYPASS_HOST_LOOP', False):
                bypass_host_loop = True
        except KeyError:
            
            
            pass
        host_results = []
        for host in notified_hosts:
            if not iterator.is_failed(host) or iterator._play.force_handlers:
                task_vars = self._variable_manager.get_vars(play=iterator._play, host=host, task=handler,
                                                            _hosts=self._hosts_cache, _hosts_all=self._hosts_cache_all)