### Summary

Ansible no longer returns distribution facts for my Amazon Linux 2 instances after #73767.

### Issue Type

Bug Report

### Component Name

setup

### Ansible Version

```console (paste below)
$ ansible --version
ansible [core 2.11.0b2.post0]  (detached HEAD 30c465c1a9) last updated 2021/03/17 18:53:46 (GMT -400)
  config file = /home/ec2-user/ansible-aws-coll/ansible/ansible.cfg
  configured module search path = ['/home/ec2-user/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/ec2-user/tmp/ansible/lib/ansible
  ansible collection location = /home/ec2-user/ansible-aws-coll/ansible/collections
  executable location = /home/ec2-user/tmp/ansible/bin/ansible
  python version = 3.8.5 (default, Feb 18 2021, 01:24:20) [GCC 7.3.1 20180712 (Red Hat 7.3.1-12)]
  jinja version = 2.11.3
  libyaml = True
```


### Configuration

```console (paste below)
$ ansible-config dump --only-changed
DEVEL_WARNING(env: ANSIBLE_DEVEL_WARNING) = False
```


### OS / Environment

Amazon Linux 2

### Steps to Reproduce

```
ansible localhost -m setup | grep distribution
```


### Expected Results

With 78d3810fdf:
```
[WARNING]: No inventory was parsed, only implicit localhost is available
        "ansible_distribution": "Amazon",
        "ansible_distribution_file_parsed": true,
        "ansible_distribution_file_path": "/etc/system-release",
        "ansible_distribution_file_variety": "Amazon",
        "ansible_distribution_major_version": "2",
        "ansible_distribution_release": "NA",
        "ansible_distribution_version": "2",
```

### Actual Results

```console (paste below)
[WARNING]: No inventory was parsed, only implicit localhost is available
```

self.module = module
    def get_distribution_facts(self):
        distribution_facts = {}
        
        
        
        system = platform.system()
        distribution_facts['distribution'] = system
        distribution_facts['distribution_release'] = platform.release()
        distribution_facts['distribution_version'] = platform.version()
        systems_implemented = ('AIX', 'HP-UX', 'Darwin', 'FreeBSD', 'OpenBSD', 'SunOS', 'DragonFly', 'NetBSD')
        if system in systems_implemented:
            cleanedname = system.replace('-', '')
            distfunc = getattr(self, 'get_distribution_' + cleanedname)
            dist_func_facts = distfunc()
            distribution_facts.update(dist_func_facts)
        elif system == 'Linux':
            distribution_files = DistributionFiles(module=self.module)
            
            dist_file_facts = distribution_files.process_dist_files()
            distribution_facts.update(dist_file_facts)
        distro = distribution_facts['distribution']
        
        distribution_facts['os_family'] = self.OS_FAMILY.get(distro, None) or distro
        return distribution_facts
    def get_distribution_AIX(self):