The following `test_irb_fg_jobs_and_kill_commands` expects that after `fg 0`
Thread#1 should be `sleep_forever`.

```ruby
    def test_irb_fg_jobs_and_kill_commands
      out = run_ruby_file do
        type "irb"
        type "fg 0"
        type "jobs"
        type "kill 1"
        type "exit"
      end

      assert_match(/#0->irb on main \(#<Thread:0x.+ run>: running\)/, out)
      assert_match(/ruby#1->irb#1 on main \(#<Thread:0x.+ sleep_forever>: stop\)/, out)
    end
  end
```

However, the following switching method expects that

```
    def switch(key)
      th, irb = search(key)
      ...
      th.run
      Thread.stop
```

(1) resume target thread
(2) Suspend current thread (-> sleep_forever)

`th.run` calls `Thread.pass` internally and maybe the context swtich to
resumed thread (#0 in this case).

Thread #0 should switch to ruby#1 before `jobs` command.
Until Ruby 3.4, I/O operation makes context switching to another ready thread,
so that several I/O output can resume `ruby#1`.

However, our planning new thread scheduler delays context switching on I/O
operations, so the thread ruby#1 still running (because `Thread.stop` is not called yet).

This patch add `Thraed.pass` to make workaround for this test.