Add e2e tests for CPU startup boost

[kamarabbas99]

What type of PR is this?

e2e tests

What this PR does / why we need it:

This PR adds the e2e tests for CPU startup boost

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

- [KEP]: (https://github.com/kubernetes/autoscaler/tree/master/vertical-pod-autoscaler/enhancements/7862-cpu-startup-boost#aep-7862-cpu-startup-boost)

NONE

[k8s-ci-robot]

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[kamarabbas99]

/cc omerap12 adrianmoisey laoj2

[kamarabbas99]

/area vertical-pod-autoscaler

[omerap12]

Overall looks good to me, but I wasn't able to run the tests locally.
I exported the following:

export FEATURE_GATES=CPUStartupBoost=true

And changed this:

diff --git a/vertical-pod-autoscaler/hack/run-e2e-tests.sh b/vertical-pod-autoscaler/hack/run-e2e-tests.sh
index f7f724925..9447abc82 100755
@@ -50,7 +50,7 @@ case ${SUITE} in
   recommender|updater|admission-controller|actuation|full-vpa)
     export KUBECONFIG=$HOME/.kube/config
     pushd ${SCRIPT_ROOT}/e2e
-    go test ./v1/*go -v --test.timeout=150m --args --ginkgo.v=true --ginkgo.focus="\[VPA\] \[${SUITE}\]" --report-dir=${WORKSPACE} --disable-log-dump --ginkgo.timeout=150m
+    go test ./v1/*go -v --test.timeout=150m --args --ginkgo.v=true --ginkgo.focus="\[VPA\] \[${SUITE}\]" --report-dir=${WORKSPACE} --ginkgo.label-filter="FG:CPUStartupBoost" --disable-log-dump --ginkgo.timeout=150m
     V1_RESULT=$?
     popd
     echo v1 test result: ${V1_RESULT}

But when I run this:

./vertical-pod-autoscaler/hack/run-e2e-locally.sh updater

I get this:

[sig-autoscaling] [VPA] [updater] [v1] Updater Unboost pods when they become Ready [FG:CPUStartupBoost]
/home/ubuntu/autoscaler/vertical-pod-autoscaler/e2e/v1/updater.go:224
  STEP: Creating a kubernetes client @ 10/27/25 12:23:28.748
  I1027 12:23:28.748322 70130 util.go:453] >>> kubeConfig: /home/ubuntu/.kube/config
  STEP: Building a namespace api object, basename vertical-pod-autoscaling @ 10/27/25 12:23:28.749
  STEP: Waiting for a default service account to be provisioned in namespace @ 10/27/25 12:23:28.757
  STEP: Waiting for kube-root-ca.crt to be provisioned in namespace @ 10/27/25 12:23:28.76
  STEP: Checking CPUStartupBoost cluster feature gate is on @ 10/27/25 12:23:28.762
  STEP: Checking CPUStartupBoost VPA feature gate is enabled for updater @ 10/27/25 12:23:28.762
  STEP: Setting up the Admission Controller status @ 10/27/25 12:23:28.764
  STEP: Setting up a hamster Deployment @ 10/27/25 12:23:28.764
  I1027 12:23:28.769598   70130 warnings.go:110] "Warning: would violate PodSecurity \"restricted:latest\": allowPrivilegeEscalation != false (container \"hamster\" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container \"hamster\" must set securityContext.capabilities.drop=[\"ALL\"]), runAsNonRoot != true (pod or container \"hamster\" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container \"hamster\" must set securityContext.seccompProfile.type to \"RuntimeDefault\" or \"Localhost\")"
  I1027 12:23:28.771252 70130 deployment.go:104] deployment status: v1.DeploymentStatus{ObservedGeneration:0, Replicas:0, UpdatedReplicas:0, ReadyReplicas:0, AvailableReplicas:0, UnavailableReplicas:0, TerminatingReplicas:(*int32)(nil), Conditions:[]v1.DeploymentCondition(nil), CollisionCount:(*int32)(nil)}
  STEP: Setting up a VPA CRD @ 10/27/25 12:23:30.778
  I1027 12:23:30.778948 70130 util.go:453] >>> kubeConfig: /home/ubuntu/.kube/config
  I1027 12:23:30.803540 70130 util.go:453] >>> kubeConfig: /home/ubuntu/.kube/config
  STEP: Annotating pods with boost annotation @ 10/27/25 12:23:30.818
  STEP: Waiting for pods to be in-place updated @ 10/27/25 12:23:31.096
  I1027 12:23:31.096062 70130 common.go:585] waiting for at least one pod to be updated without eviction
  I1027 12:25:31.099681 70130 common.go:629] finished waiting for at least one pod to be updated without eviction
  STEP: Deleting the Admission Controller status @ 10/27/25 12:25:31.099
  [FAILED] in [It] - /home/ubuntu/autoscaler/vertical-pod-autoscaler/e2e/v1/updater.go:252 @ 10/27/25 12:25:31.103
  STEP: Destroying namespace "vertical-pod-autoscaling-9135" for this suite. @ 10/27/25 12:25:31.104
• [FAILED] [122.361 seconds]
[sig-autoscaling] [VPA] [updater] [v1] Updater [It] Unboost pods when they become Ready [FG:CPUStartupBoost]
/home/ubuntu/autoscaler/vertical-pod-autoscaler/e2e/v1/updater.go:224

  [FAILED] Unexpected error:
      <context.deadlineExceededError>: 
      context deadline exceeded
      
          {}
  occurred
  In [It] at: /home/ubuntu/autoscaler/vertical-pod-autoscaler/e2e/v1/updater.go:252 @ 10/27/25 12:25:31.103
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Anything I forgot to do?
(when @adrianmoisey PRs will be merged this process will be much better )