Automatic merge from submit-queue (batch tested with PRs 53418, 53366, 53115, 53402, 53130). 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>.
Implement delete real server for fakeIPVS and add UTs
**What this PR does / why we need it**:
* Implement DeleteRealServer() for FakeIPVS because ipvs/proxier needs it.
* Add UTs - Since there are some real logics in fakeIPVS interface, it's important to add some UTs which can help avoiding some mistakes. Sadly, there is already a bug :(
**Which issue this PR fixes**:
fixes#53137
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 53227, 53120). 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>.
remove ipv4 in pkg/util/ipvs
**What this PR does / why we need it**:
remove ipv4 in util/ipvs
**Which issue this PR fixes**:
xref: #51866
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
