### 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

...
except Exception as ex:
                failed.append(target)
                if args.continue_on_error:
                    display.error(ex)
                    continue
                display.notice('To resume at this test target, use the option: --start-at %s' % target.name)
                next_target = next(targets_iter, None)
                if next_target:
                    display.notice('To resume after this test target, use the option: --start-at %s' % next_target.name)
                raise
            finally:
                display.verbosity = args.verbosity = verbosity
    finally:
        if not args.explain:
            if args.coverage:
                coverage_temp_path = os.path.join(common_temp_path, ResultType.COVERAGE.name)
                coverage_save_path = ResultType.COVERAGE.path
                for filename in os.listdir(coverage_temp_path):
                    shutil.copy(os.path.join(coverage_temp_path, filename), os.path.join(coverage_save_path, filename))
            remove_tree(common_temp_path)
            result_name = '%s-%s.json' % (
                args.command, re.sub(r'[^0-9]', '-', str(datetime.datetime.utcnow().replace(microsecond=0))))
            data = dict(
                targets=results,
            )
            write_json_test_results(ResultType.DATA, result_name, data)
    if failed:
        raise ApplicationError('The %d integration test(s) listed below (out of %d) failed. See error output above for details:\n%s' % (
            len(failed), len(passed) + len(failed), '\n'.join(target.name for target in failed)))
def start_httptester(args):