[$] Reconsidering the scheduler's wake_wide() heuristic

The kernel's CPU scheduler is charged with choosing which task to run next,but also with deciding where in a multi-CPU system that task should run.As is often the case, that choice comes down to heuristics - rules of thumbcodifying the developers' experience of what tends to work best. One keytask-placement heuristic has been in place since 2015, but a recentdiscussion suggests that it may need to be revisited.