In 44142e5f I removed this code, under the belief that it wasn't
a problem. However, when WpfFact-attributed tests run, we clear the
foreground thread. Some static state (namely the
ForegroundNotificationService) is still trying to operate between test
runs, so it'd see the fallback state and then bad things would happen.
Although there's a number of terrifying things there, for now we'll
just roll it back.

Use tuple syntax in the compiler

This change makes foreground scheduling code predictable in the IDE
tests.  Instead of using a static to hold the data we use instance
values.  The static data the instance values are populated from are not
100% predictable but far more so than they used to be.