Automatic merge from submit-queue (batch tested with PRs 52486, 52588, 52524). 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 nil pointer dereference in cri stats provider when there are no image file systems
**What this PR does / why we need it**:
This PR fixes a nil pointer dereference in CRI stats provider when there are no image filesystems. See https://github.com/kubernetes/kubernetes/pull/51152 for discussion.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
```
/cc yujuhong yguo0905
02731cc767