fix(call): Duplicate CANCEL issue when CANCEL ALL

* Fixed the problem that the program was canceled in duplicate by the recurrence function and loop processing.

Author: n-isaka

libcob/call.c

@@ -316,10 +316,8 @@ cob_cancel_call_stack_list (struct call_stack_list *p)
 	if (p->children) {
 		cob_cancel_call_stack_list (p->children);
 	}
-	struct call_stack_list *s = p->sister;
-	while (s != NULL) {
-		cob_cancel_call_stack_list (s);
-		s = s->sister;
+	if (p->sister) {
+		cob_cancel_call_stack_list (p->sister);
 	}
 }