Also they bypass the 'single stdout' restriction

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
collections

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.8, 2.9
```

##### 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. -->
any

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
put callback into collection and whitelist
<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

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

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
callback works

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
callback options are ignored
<!--- Paste verbatim command output between quotes -->
```paste below

```

'''
    This class handles the multiprocessing requirements of Ansible by
    creating a pool of worker forks, a result handler fork, and a
    manager object with shared datastructures/queues for coordinating
    work between all processes.
    The queue manager is responsible for loading the play strategy plugin,
    which dispatches the Play's tasks to hosts.
    '''
    RUN_OK = 0
    RUN_ERROR = 1
    RUN_FAILED_HOSTS = 2
    RUN_UNREACHABLE_HOSTS = 4
    RUN_FAILED_BREAK_PLAY = 8
    RUN_UNKNOWN_ERROR = 255
    def __init__(self, inventory, variable_manager, loader, passwords, stdout_callback=None, run_additional_callbacks=True, run_tree=False, forks=None):
        self._inventory = inventory
        self._variable_manager = variable_manager
        self._loader = loader
        self._stats = AggregateStats()
        self.passwords = passwords
        self._stdout_callback = stdout_callback
        self._run_additional_callbacks = run_additional_callbacks
        self._run_tree = run_tree
        self._forks = forks or 5
        self._callbacks_loaded = False
        self._callback_plugins = []
        self._start_at_done = False
        
        if context.CLIARGS.get('module_path', False):
            for path in context.CLIARGS['module_path']: