Intermittent random problems in the Windows leg of the build pipeline

[dumbledad]

See, for example, these failures:

INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\_pytest\main.py", line 240, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\_pytest\main.py", line 296, in _main
INTERNALERROR>     config.hook.pytest_runtestloop(session=session)
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\pluggy\hooks.py", line 286, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\pluggy\manager.py", line 93, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\pluggy\manager.py", line 87, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\pluggy\callers.py", line 203, in _multicall
INTERNALERROR>     gen.send(outcome)
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\pluggy\callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\pluggy\callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\xdist\dsession.py", line 112, in pytest_runtestloop
INTERNALERROR>     self.loop_once()
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\xdist\dsession.py", line 135, in loop_once
INTERNALERROR>     call(**kwargs)
INTERNALERROR>   File "c:\miniconda\envs\innereye\lib\site-packages\xdist\dsession.py", line 177, in worker_workerfinished
INTERNALERROR>     assert not crashitem, (crashitem, node)
INTERNALERROR> AssertionError: ('Tests/ML/test_model_training.py::test_valid_model_train[False]', <WorkerController gw0>)
INTERNALERROR> assert not 'Tests/ML/test_model_training.py::test_valid_model_train[False]'

AB#4254