### 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

...
test_id = docker_run(args, test_image, options=test_options)[0]
            if args.explain:
                test_id = 'test_id'
            else:
                test_id = test_id.strip()
            setup_sh = read_text_file(os.path.join(ANSIBLE_TEST_DATA_ROOT, 'setup', 'docker.sh'))
            ssh_keys_sh = get_ssh_key_setup(SshKey(args))
            setup_sh += ssh_keys_sh
            shell = setup_sh.splitlines()[0][2:]
            docker_exec(args, test_id, [shell], data=setup_sh)
            
            docker_put(args, test_id, local_source_fd.name, '/root/test.tgz')
            docker_exec(args, test_id, ['tar', 'oxzf', '/root/test.tgz', '-C', '/root'])
            
            if isinstance(args, UnitsConfig) and not args.python:
                cmd += ['--python', 'default']
            
            
            if isinstance(args, UnitsConfig):
                writable_dirs = [
                    os.path.join(content_root, ResultType.JUNIT.relative_path),
                    os.path.join(content_root, ResultType.COVERAGE.relative_path),
                ]
                docker_exec(args, test_id, ['mkdir', '-p'] + writable_dirs)
                docker_exec(args, test_id, ['chmod', '777'] + writable_dirs)
                docker_exec(args, test_id, ['chmod', '755', '/root'])
                docker_exec(args, test_id, ['chmod', '644', os.path.join(content_root, args.metadata_path)])
                docker_exec(args, test_id, ['useradd', 'pytest', '--create-home'])
                docker_exec(args, test_id, cmd + ['--requirements-mode', 'only'], options=cmd_options)
                networks = get_docker_networks(args, test_id)