Merge pull request #56097 from mtaufen/kc-file-e2e-test

Automatic merge from submit-queue (batch tested with PRs 51494, 56097, 56072, 56175). 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>.

Kubelet flags take precedence over config from files/ConfigMaps

Changes the Kubelet configuration flag precedence order so that flags
take precedence over config from files/ConfigMaps.

See:
https://docs.google.com/document/d/18-MsChpTkrMGCSqAQN9QGgWuuFoK90SznBbwVkfZryo/

Also modifies e2e node test suite to transform all relevant Kubelet flags into
a config file before starting tests when the KubeletConfigFile feature gate is
true, and turns on the KubeletConfigFile gate for all e2e node tests.
This allows the alpha dynamic Kubelet config feature to continue to 
work in tests after the precedence change.

fixes #56171

Related: https://github.com/kubernetes/features/issues/281


```release-note
CLI flags passed to the Kubelet now take precedence over Kubelet config files and dynamic Kubelet config. This helps ensure backwards compatible behavior across Kubelet binary updates.
```

hack/make-rules/test.sh

@@ -69,6 +69,7 @@ kube::test::find_dirs() {
         -o -path './vendor/k8s.io/client-go/*' \
         -o -path './vendor/k8s.io/apiserver/*' \
         -o -path './test/e2e_node/system/*' \
+        -o -path './test/e2e_node/services/*' \
       -name '*_test.go' -print0 | xargs -0n1 dirname | sed "s|^\./|${KUBE_GO_PACKAGE}/|" | LC_ALL=C sort -u
 
     # run tests for client-go