[8.18] (backport #7931) [ci] migrate extended runtime leak tests to buildkite

[mergify]

What does this PR do?

This PR migrates the Extended Runtime Leak Tests to Buildkite, where all other integration and Kubernetes tests now reside. The new setup runs these tests on Windows 2022, Windows 2025, and Ubuntu 24.04 using existing prebuilt VM images. The old step is removed to avoid duplication and eliminate the dependency on OGC.

Proof that we run the same tests:

• Before this PR
• With this PR Windows 2022, With this PR Windows 2025, With this PR Ubuntu 24.04

Why is it important?

This resolves reliability issues in the old extended testing setup, aligning them with our current CI strategy and infrastructure.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

None. This change only affects internal CI configuration.

How to test this PR locally

Open a PR 🙂

Related issues

• Closes https://github.com/elastic/ingest-dev/issues/5269

---

This is an automatic backport of pull request #7931 done by [Mergify](https://mergify.com).

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 8eb49b3

History

• 💔 Build #21783 failed 8eb49b3
• 💔 Build #21756 failed 8eb49b3
• 💔 Build #21736 failed 8eb49b3

cc @pkoutsovasilis