### 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

...
inventory_path = os.path.join(data_context().content.root, data_context().content.integration_path, args.inventory)
    else:
        inventory_path = os.path.join(data_context().content.root, inventory_relative_path)
    if not args.explain and not args.windows and not os.path.isfile(inventory_path):
        raise ApplicationError(
            'Inventory not found: %s\n'
            'Use --inventory to specify the inventory path.\n'
            'Use --windows to provision resources and generate an inventory file.\n'
            'See also inventory template: %s' % (inventory_path, template_path)
        )
    check_inventory(args, inventory_path)
    delegate_inventory(args, inventory_path)
    all_targets = tuple(walk_windows_integration_targets(include_hidden=True))
    internal_targets = command_integration_filter(args, all_targets, init_callback=windows_init)
    instances = []  
    pre_target = None
    post_target = None
    httptester_id = None
    if args.windows:
        get_python_path(args, args.python_executable)  
        configs = dict((config['platform_version'], config) for config in args.metadata.instance_config)
        for version in args.windows:
            config = configs['windows/%s' % version]
            instance = WrappedThread(functools.partial(windows_run, args, version, config))
            instance.daemon = True
            instance.start()
            instances.append(instance)
        while any(instance.is_alive() for instance in instances):
            time.sleep(1)
        remotes = [instance.wait_for_result() for instance in instances]