feature request: make `--dist worksteal` the default

[charles-cooper]

i have been finding that --dist worksteal is generally more performant than --dist load -- sometimes substantially. ideally, --dist worksteal should be the default, since it's simply a better algorithm. this would also address https://github.com/pytest-dev/pytest-xdist/issues/890 by making the other schedulers (loadfile, loadgroup etc) include work stealing.

[amezin]

No, it won't magically make file/group/scope schedulers do work-stealing based scheduling

[charles-cooper]

No, it won't magically make file/group/scope schedulers do work-stealing based scheduling

ah, right, my suggestion was that the other schedulers could use workstealing instead of what they are doing right now. i did not mean to imply that it would happen magically!