### Summary

I know there is some ongoing work to mitigate these problems, but since I'm not aware which parts have already been addressed and which not, I want to share some common failures here which I've seen during the last days:

1. When running `ansible-test sanity --color -v --junit --coverage-check --changed --docker --base-branch origin/main --skip-test pylint --skip-test ansible-doc --skip-test validate-modules --allow-disabled` in CI, the Python 2.6 `import` test fails:
```
02:05 ERROR: Command "/root/ansible_collections/community/general/tests/output/.tmp/sanity/import/minimal-py26/bin/python /root/ansible/test/lib/ansible_test/_data/quiet_pip.py install --disable-pip-version-check coverage -c /root/ansible/test/lib/ansible_test/_data/requirements/constraints.txt" returned exit status 1.
02:05 >>> Standard Error
02:05 Could not find a version that satisfies the requirement coverage<5.0.0,>=4.5.1 (from -c /root/ansible/test/lib/ansible_test/_data/requirements/constraints.txt (line 2)) (from versions: )
02:05 No matching distribution found for coverage<5.0.0,>=4.5.1 (from -c /root/ansible/test/lib/ansible_test/_data/requirements/constraints.txt (line 2))
02:05 >>> Standard Output
02:05 Collecting coverage<5.0.0,>=4.5.1 (from -c /root/ansible/test/lib/ansible_test/_data/requirements/constraints.txt (line 2))
```
(See https://app.shippable.com/github/ansible-collections/community.general/runs/8257/1/console for the full log)

2. When running unit tests for Python 2.6 with `ansible-test units -v --color --docker --coverage` with `unittest2 ; python_version < '2.7'` in tests/unit/requirements.txt, it fails:
```
Run command: /usr/bin/python2.6 /root/ansible/test/lib/ansible_test/_data/quiet_pip.py install --disable-pip-version-check -r /root/ansible/test/lib/ansible_test/_data/requirements/units.txt -r tests/unit/requirements.txt coverage -c /root/ansible/test/lib/ansible_test/_data/requirements/constraints.txt
Collecting unittest2 (from -r tests/unit/requirements.txt (line 1))
  Could not find a version that satisfies the requirement unittest2 (from -r tests/unit/requirements.txt (line 1)) (from versions: )
No matching distribution found for unittest2 (from -r tests/unit/requirements.txt (line 1))
ERROR: Command "/usr/bin/python2.6 /root/ansible/test/lib/ansible_test/_data/quiet_pip.py install --disable-pip-version-check -r /root/ansible/test/lib/ansible_test/_data/requirements/units.txt -r tests/unit/requirements.txt coverage -c /root/ansible/test/lib/ansible_test/_data/requirements/constraints.txt" returned exit status 1.
```
(See https://github.com/ansible-collections/community.hrobot/runs/2264772861?check_suite_focus=true)


### Issue Type

Bug Report

### Component Name

ansible-test

### Ansible Version

```console (paste below)
devel
```


### Configuration

...

### OS / Environment

...

### Steps to Reproduce

...

### Expected Results

...

### Actual Results

...
self.docker_seccomp = get_docker_completion().get(self.docker_raw, {}).get('seccomp', 'default')
        self.remote_stage = args.remote_stage  
        self.remote_provider = args.remote_provider  
        self.remote_endpoint = args.remote_endpoint  
        self.remote_terminate = args.remote_terminate  
        if self.remote_provider == 'default':
            self.remote_provider = None
        self.requirements = args.requirements  
        if self.python == 'default':
            self.python = None
        actual_major_minor = '.'.join(str(i) for i in sys.version_info[:2])
        self.python_version = self.python or actual_major_minor
        self.python_interpreter = args.python_interpreter
        self.pip_check = args.pip_check
        self.delegate = self.docker or self.remote or self.venv
        self.delegate_args = []  
        if self.delegate:
            self.requirements = True
        self.inject_httptester = args.inject_httptester if 'inject_httptester' in args else False  
        self.httptester = docker_qualify_image(args.httptester if 'httptester' in args else '')  
        krb5_password = args.httptester_krb5_password if 'httptester_krb5_password' in args else ''
        self.httptester_krb5_password = krb5_password or generate_password()  
        if self.get_delegated_completion().get('httptester', 'enabled') == 'disabled':
            self.httptester = False
        if self.get_delegated_completion().get('pip-check', 'enabled') == 'disabled':
            self.pip_check = False
        if args.check_python and args.check_python != actual_major_minor:
            raise ApplicationError('Running under Python %s instead of Python %s as expected.' % (actual_major_minor, args.check_python))
        if self.docker_keep_git:
            def git_callback(files):