scheduler_affine: Add logic shared with simple scheduler

The scheduler is in very early stage. There is no thread migration and
the algorithms choosing CPU for thread are very simple.

Since affine scheduler is going to use one run queue per core simple on
single core machines it will work exactly the same as simple scheduler.
That would allow us to have only one scheduler implementation usable
on all kinds of machines.

src/system/kernel/scheduler/scheduler_simple.cpp

@@ -162,9 +162,12 @@ dump_run_queue(int argc, char** argv)
 		return 0;
 
 	for (int32 i = 0; i < cpuCount; i++) {
-		kprintf("\nCPU %d run queue:\n", i);
-		sCPURunQueues[i].GetConstIterator();
-		dump_queue(iterator);
+		iterator = sCPURunQueues[i].GetConstIterator();
+
+		if (iterator.HasNext()) {
+			kprintf("\nCPU %" B_PRId32 " run queue:\n", i);
+			dump_queue(iterator);
+		}
 	}
 
 	return 0;