Speedup test fails on loaded machine

In a integration test this has been observed:

```
FAILED tests/test_linear_regression.py::test_parallel_speedup - AssertionError: Parallel (14.20s) should be faster than sequential (12.76s)
```

The assumptions for such a test is probably that there are multiple otherwise idling cpu-cores available when running the test. Such an assumption does not hold when running integration tests.

https://github.com/equinor/komodo-releases/actions/runs/23488889334/job/68352480439