[flaky test] Generate non-overlapping and non-mergable CIDRs with best effort

[zarvd]

What type of PR is this?

/kind testing

What this PR does / why we need it:

https://prow.k8s.io/view/gs/kubernetes-ci-logs/pr-logs/pull/kubernetes-sigs_cloud-provider-azure/8521/pull-cloud-provider-azure-unit-1-31/1897178703616544768

The root cause of the flaky test is that the random fixture occasionally generates overlapping or mergeable CIDRs, which disrupts the comparison and assertions in the test. This PR resolves the issue in the access control flaky test by generating CIDRs with a larger bit size, ensuring that no overlapping CIDRs are produced in a single run—sufficient for the existing test case.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

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

[k8s-ci-robot]

Hi @zarvd. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[nilo19]

/ok-to-test

[nilo19]

do we need to put the flaky one into a for loop to make it run multiple times each time?

[zarvd]

do we need to put the flaky one into a for loop to make it run multiple times each time?

The problem is with the test fixture, not the function itself, so I think we can just skip it.

I also have a pending PR #7190 to merge destination CIDRs, and I might refactor the test fixture in that PR to make it more predictable.

[feiskyer]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: feiskyer, zarvd

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[k8s-ci-robot]

New changes are detected. LGTM label has been removed.