Jump and Throw need to store the term away, if they try to use arena

the term will hang in the stack (#152).

C/init.c

@@ -1199,6 +1199,7 @@ InitCodes(void)
   Yap_heap_regs->wl.consultbase = Yap_heap_regs->wl.consultsp =
     Yap_heap_regs->wl.consultlow + Yap_heap_regs->wl.consultcapacity;
 #endif /* YAPOR */
+  Yap_heap_regs->wl.ball_term = NULL;
 
   /* make sure no one else can use these two atoms */
   CurrentModule = 0;