Koichi Sasada 7b75b1f2da prepare IDs for Ractor::monitor
To prevent the following strange error, prepare IDs at first.

```
     <internal:ractor>:596:in 'Ractor#monitor': symbol :exited is already registered with 98610c (fatal)
             from <internal:ractor>:550:in 'Ractor#join'
             from <internal:ractor>:574:in 'Ractor#value'
             from bootstraptest.test_ractor.rb_2013_1309.rb:12:in '<main>'
```

BTW, the error should be fixed on ID management system.
2025-05-31 18:29:02 +09:00
..
2025-05-31 18:29:02 +09:00