为什么Simulator的Close方法需要创建一个test Pod并且等待其调度结束

## Question

如果在[这一行](https://github.com/alibaba/open-simulator/blob/c11c72ed298fa8b2174fa94394fb32c5c5e03478/pkg/simulator/core.go#LL87C3-L87C3)报错了，defer的Close方法会阻塞，因为scheduler还没运行起来，test pod永远不会返回调度结果，因此会阻塞在sim.simulatorStop这个chan上。

复现方法：删除[这一行](https://github.com/alibaba/open-simulator/blob/main/pkg/test/pod.go#LL31C7-L31C7)之后，执行测试pkg/simulator/core_test.go，就会阻塞住。

如果要修复这个问题，可以在生成Pod之后再NewSimulator。这样如果生成失败，也不需要Close simulator了

但我的疑问是为什么Simulator的Close方法需要创建一个test Pod并且等待其调度结束？去掉test Pod的话会有什么问题？

Read pkg/simulator/core.go around line 87 and inspect how Close waits on sim.simulatorStop. Then review pkg/test/pod.go around line 31 and run pkg/simulator/core_test.go with that line removed to reproduce the block. Done means the lifecycle behavior is explained and the test no longer hangs when simulator startup fails.

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