Running test leaves junk on tmp folder

[kif]

Silx tests:
https://github.com/silx-kit/silx/blob/main/src/silx/io/test/test_nxdata.py#L489

Does not clean up data

[t20100]

Yes, we should clean-up all the different ways to handle temporary files in the tests

[kif]

I can submit a patch for this one ... but a general fix for all silx is much more work (not a pytest saavy).