Automatic merge from submit-queue (batch tested with PRs 60898, 60912, 60753, 61002, 60796). 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>.
Fix TODO: move openHostPorts and closeHostPorts into a common struct and add UTs
**What this PR does / why we need it**:
* Fix [TODO](https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/network/hostport/hostport.go#L132): move openHostPorts and closeHostPorts into a common struct, and eliminate the `hostportOpener` parameter in openHostPorts(), to make them looks more consistent.
* Add UTs for closeHostPorts.
**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
```
6a431d1c0e