tests/vm/netbsd: Use Python v3.11

tests/vm/netbsd: Use Python v3.11

We requiere the 'ninja-build', which depends on 'python311':

  $ pkgin show-deps ninja-build
  direct dependencies for ninja-build-1.11.1nb1
          python311>=3.11.0

So we end up installing both Python v3.10 and v3.11:

  [31/76] installing python311-3.11.5...
  [54/76] installing python310-3.10.13...
  [74/76] installing py310-expat-3.10.13nb1...

Then the build system picks Python v3.11, and doesn't find
py-expat because we only installed the 3.10 version:

  python determined to be '/usr/pkg/bin/python3.11'
  python version: Python 3.11.5

  *** Ouch! ***

  Python's pyexpat module is not found.
  It's normally part of the Python standard library, maybe your distribution packages it separately?
  Either install pyexpat, or alleviate the need for it in the first place by installing pip and setuptools for '/usr/pkg/bin/python3.11'.

  (Hint: NetBSD's pkgsrc debundles this to e.g. 'py310-expat'.)

  ERROR: python venv creation failed

Fix by installing py-expat for v3.11. Remove the v3.10
packages since we aren't using them anymore.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20231109150900.91186-1-philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>