### 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

...
args.exclude.append(args.changed_all_target)
    require = args.require + changes
    exclude = args.exclude
    internal_targets = walk_internal_targets(targets, args.include, exclude, require)
    environment_exclude = get_integration_filter(args, internal_targets)
    environment_exclude += cloud_filter(args, internal_targets)
    if environment_exclude:
        exclude += environment_exclude
        internal_targets = walk_internal_targets(targets, args.include, exclude, require)
    if not internal_targets:
        raise AllTargetsSkipped()
    if args.start_at and not any(target.name == args.start_at for target in internal_targets):
        raise ApplicationError('Start at target matches nothing: %s' % args.start_at)
    if init_callback:
        init_callback(args, internal_targets)
    cloud_init(args, internal_targets)
    vars_file_src = os.path.join(data_context().content.root, data_context().content.integration_vars_path)
    if os.path.exists(vars_file_src):
        def integration_config_callback(files):  
            """
            Add the integration config vars file to the payload file list.
            This will preserve the file during delegation even if the file is ignored by source control.
            """
            files.append((vars_file_src, data_context().content.integration_vars_path))
        data_context().register_payload_callback(integration_config_callback)
    if args.delegate:
        raise Delegate(require=require, exclude=exclude, integration_targets=internal_targets)
    install_command_requirements(args)
    return internal_targets
def command_integration_filtered(args, targets, all_targets, inventory_path, pre_target=None, post_target=None,