Reschedule immediately in many cases

I have not carefully tested each of these, but they are generally in line with my previous testing.  I may go ahead and test many of them with better-priority threads, but feedback from testing to see if it breaks games would be appreciated.

I'm pretty sure this will fix #2188 and help #5947.  I will be very surprised if it doesn't cause problems in at least a few games though...

I'm pretty sure that thread end waits, at least, do not wake up immediately regardless of priority, but definitely need to test that more.

-[Unknown]