Automatic merge from submit-queue (batch tested with PRs 65299, 65524, 65154, 65329, 65536). 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>.

Make various fixes to flex tests and fix some crashes

* Fixes two controller-manager crashes when a flex plugin gets removed from flex directory.
* Also enables e2e tests to run in local clusters and other environments.
* Removes disruptive from flex e2e tests because flex can be installed in a running cluster and does not require kubelet or controller-manager restart anymore.

/sig storage

cc @verult @jsafrane 

```release-note
Fix controller-manager crashes when flex plugin is removed from flex plugin directory
```