Automatic merge from submit-queue. 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>.
Map correct vmset name for internal load balancers
**What this PR does / why we need it**:
When creating an internal loadbalancer, e.g.
```sh
cat << EOF | kubectl create -f -
apiVersion: v1
kind: Service
metadata:
name: ingress-nginx
annotations:
service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
type: LoadBalancer
ports:
- name: http
port: 80
targetPort: 80
protocol: TCP
- name: https
port: 443
targetPort: 443
protocol: TCP
selector:
app: ingress-nginx
EOF
```
Then wait a while, and no target backends present for the internal load balancer even after 15 mins.
Refer https://github.com/Azure/acs-engine/issues/2151#issuecomment-364726846.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#59746
**Special notes for your reviewer**:
Should cherry pick to v1.9, v1.8, and v1.7 (and requires resolving conflicts manually).
**Release note**:
```release-note
Map correct vmset name for internal load balancers
```
4cc993a720
