* use nightly
* switch ml cpu to ray cpu
* fix
* add pytest
* add more pytest
* add constraint
* add tensorflow
* fix merge conflict
* add tblib
* fix
* add back uninstall
## Why are these changes needed?
There are two issues fixed in this PR:
- make sure wait for session count alive node
- upgrade the machine to match what's tested in oss ray.
## Related issue number
https://github.com/ray-project/ray/issues/19084
When testing it we should minimize unnecessary env vars (and it's better working with the default config). This PR removes unnecessary env vars that are set.