Automatic merge from submit-queue (batch tested with PRs 59489, 59716). 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>.

devicemanager testing: dynamically choose tmp dir

This avoids the test issue #59488 that I was running into.

I believe I have a reasonable explanation for the race condition in that issue (TLDR: it's probably part of the gRPC API and k8s can only avoid the issue until a proper solution gets worked out together with gRPC), therefore I suggest to merge this PR now both because it avoids the issue and because using fixed tmp directories is something that should be avoided anyway.

/assign @jiayingz