[8.9](backport #3097) Fix flaky TestFQDN

[mergify]

This is an automatic backport of pull request #3097 done by Mergify.
Cherry-pick of d2162bb has failed:

On branch mergify/bp/8.9/pr-3097
Your branch is up to date with 'origin/8.9'.

You are currently cherry-picking commit d2162bbb4f.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   testing/integration/fqdn_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   docs/test-framework-dev-guide.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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• Start Time: 2023-07-20T06:49:50.888+0000

• Duration: 21 min 2 sec

Test stats 🧪

Test	Results
Failed	0
Passed	5979
Skipped	23
Total	6002

💚 Flaky test report

Tests succeeded.

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[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	98.684% (75/76)	👍
Files	67.3% (177/263)	👍
Classes	66.802% (328/491)	👍
Methods	53.481% (1014/1896)	👍
Lines	39.293% (11551/29397)	👎 -0.034
Conditionals	100.0% (0/0)	💚