T: bug fixes for the T cache

- 'busy' has to be handled in a more atomic fashion to avoid crazy
  runtime race conditions
- the basic simulator is too fast sometimes; rewrite the accesses to
  the T cache to avoid there again crazy behaviors

Hopefully that's better...

common/utils/T/local_tracer.c

@@ -337,7 +337,7 @@ static void forward(void *_forwarder, char *buf, int size)
 
 static void wait_message(void)
 {
-  while (T_local_cache[T_busylist_head].busy == 0) usleep(1000);
+  while ((T_local_cache[T_busylist_head].busy & 0x02) == 0) usleep(1000);
 }
 
 void T_local_tracer_main(int remote_port, int wait_for_tracer,