Fixed a task suspend/resume scheduler issue.

- Scheduler was increasing total priorities only when resuming tasks had 0 ticks.
This caused forked tasks that have parent's share of ticks to finish their jobs,
if these tasks exited quick enough, they would cause the total priorities to deduce
without increasing it in the first place. This is now fixed.

- Also strengthened rq locking, now both queues are locked before touching any.
- Also removed task suspends in irq, this would cause a race condition on ticks and
  runqueues, since neither is protected against irqs.

src/generic/irq.c

@@ -75,8 +75,16 @@ void do_irq(void)
 	}
 	irq_enable(irq_index);
 
+#if 0
 	/* Process any pending flags for currently runnable task */
-	task_process_pending_flags();
+	if (!in_nested_irq_context()) {
+		/* This is buggy, races on prio_total */
+		if (in_user()) {
+			if (current->flags & TASK_SUSPENDING)
+				sched_suspend_async();
+		}
+	}
+#endif
 }