Test badrand in start.c

kern/start.c

@@ -93,6 +93,10 @@ void start() {
             astatus = rtc_alarm_status();
             assert(astatus == 1);
         }
+        {
+            uint64_t rn = badrand();
+            assert(rn != badrand());
+        }
         {
             char buffer[128];
             badrand_buf(buffer, 128);