[Coscheduling] test: need a integration test for PodGroup Status

[zwpaper]

we have an integration test for coscheduling, https://github.com/kubernetes-sigs/scheduler-plugins/blob/master/test/integration/coscheduling_test.go, but it did not test the PodGroup status.

if PodGroup Status is not functionally working, we can not found the issue

[Huang-Wei]

We didn't invest too much effort in the controller's quality TBH. We can polish the controller code, along with adequate tests once we finish the migration to ctrl-runtime.

[Gekko0114]

Hi @zwpaper ,
Can I work on this issue if you don't plan to work on it?

[zwpaper]

Hi @Gekko0114, feel free to take and work on it!

/assign @Gekko0114