Automatic merge from submit-queue (batch tested with PRs 58412, 56132, 58506, 58542, 58394). 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 upgrade-aliases.sh to migrate a route-based k8s cluster to use IP aliases in GCE.
**What this PR does / why we need it**:
This PR implements upgrade-aliases.sh, which is used to migrate a route-based k8s cluster to use IP aliases in GCE.
**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 #
**Special notes for your reviewer**:
**Release note**:
```release-note
"NONE"
```
854adeb2d7