[BUG] check why linux tests now same speed as windows, and why/if linux test got slowr

[jiata]

Description

Dataset name	Time env installation	Time tests	#tests		Time integration test for  IC test_03_notebook_run	Time unit test for  IC test_03_notebook_run		Comment
Linux GPU	3:20min	22min	74		183sec	19 sec		On Aug 22nd, the IC integration 03 test took 57 sec
Linux CPU	4:30min	5min	66			27 sec
Windows GPU	9:20min	10min	66			16 sec
Windows CPU	14min	11min	66			26 sec
AzureML notebooks

[PatrickBue]

@jiata Can I close this?
Not sure if it's related, but I made some updates which speed up the windows tests (mainly for image classification and image similarity, but also for the other scenarios. Turns out PyTorch's dataloader when using >1 workers in windows gets very slow. Hence the number of workers is now automatically set to 1 for windows machines (and if on Binder, that was to fix an otherwise occurring error)