Automatic merge from submit-queue (batch tested with PRs 61003, 61031, 60360, 58349, 60922). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
move `newUDPEchoServer` to proxier_test.go
move userspace proxier test code into test go file
/kind cleanup
**Release note**:
```release-note
NONE
```
7fa3c9fa63