Drop setup.py test

[xrmx]

What does this pull request do?

Remove the support for python setup.py test for compatibility with setuptools>=72 that removed the test command.
See pypa/setuptools#931

While at it remove some python 2 relics from windows scripts.

Related issues

CI failures

   × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [18 lines of output]
      <string>:60: DeprecationWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html
      Traceback (most recent call last):
        File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
        File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 118, in get_requires_for_build_wheel
          return hook(config_settings)
        File "/tmp/pip-build-env-t48opgw9/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 327, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=[])
        File "/tmp/pip-build-env-t48opgw9/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 297, in _get_build_requires
          self.run_setup()
        File "/tmp/pip-build-env-t48opgw9/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 497, in run_setup
          super().run_setup(setup_script=setup_script)
        File "/tmp/pip-build-env-t48opgw9/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 313, in run_setup
          exec(code, locals())
        File "<string>", line 62, in <module>
      ModuleNotFoundError: No module named 'setuptools.command.test'
      [end of output]