This test results in an error 'No pyvenv.cfg file' on the Windows 2019 runner:

    [...]
    File "D:\a\nox\nox\tests\test_virtualenv.py", line 438, in test_create_reuse_oldstyle_virtualenv_environment
      reused = not venv.create()
    File "d:\a\nox\nox\nox\virtualenv.py", line 420, in create
      if not self._clean_location():
    File "d:\a\nox\nox\nox\virtualenv.py", line 313, in _clean_location
      and self._check_reused_environment_interpreter()
    File "d:\a\nox\nox\nox\virtualenv.py", line 342, in _check_reused_environment_interpreter
      ["python", "-c", program], silent=True, log=False, paths=self.bin_paths
    File "d:\a\nox\nox\nox\command.py", line 118, in run
      full_cmd, return_code, ":" if silent else ""
  Message: "Command python -c import sys; print(getattr(sys, 'real_prefix', sys.base_prefix)) failed with exit code 106:"
  Arguments: ()
  No pyvenv.cfg file

  ------------------------------ Captured log call ------------------------------
  INFO     nox:virtualenv.py:440 Creating virtual environment (virtualenv) using python.exe in D:\a\nox\nox\.nox\tests-3-7\tmp\pytest-of-runneradmin\pytest-0\test_create_reuse_oldstyle_vir0\venv
  ERROR    nox:command.py:118 Command python -c import sys; print(getattr(sys, 'real_prefix', sys.base_prefix)) failed with exit code 106:

The error message appears to come from the Windows Python launcher (see
cpython/PC/launcher.c).

The test places a spurious occurrence of "virtualenv" in the pyvenv.cfg file, to
check for robust parsing. This was done by modifying the `home` key to point to
a fictitious installation at /opt/virtualenv/bin.

Unfortunately, this leads to the following error on Windows when determining the
Python base installation:

    No Python at '/opt/virtualenv/bin\python.exe'

Avoid this error by using an entirely bogus key, which should be ignored by
Python and other tools:

    bogus = virtualenv