[8.17](backport #41891) Invoke m.Run on TestMain and fix test flakiness

[mergify]

Proposed commit message

invoke m.Run on TestMain and reduce test flakiness

Some TestMain were not running any tests as they did not invoke m.Run. This change fixes that.

Also other tests were presenting some flakyness, therefore this change also attempts to fix the flakiness by setting really unique IDs for filestream tests and increasing a timeout for TestTranslateGUIDWithLDAP.

The following 4 packages were not running any test as the TestMain was not invoking m.Run() to actually run the test. The packages were:

• filebeat/autodiscover/builder/hints
• filebeat/processor/add_kubernetes_metadata
• metricbeat/autodiscover/appender/kubernetes/token
• metricbeat/autodiscover/builder/hints

Checklist

• 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.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Disruptive User Impact

• N/A

How to test this PR locally

Run the test for the affected packages, the tests should run.

go test -v ./filebeat/autodiscover/builder/hints
go test -v ./filebeat/processor/add_kubernetes_metadata
go test -v ./metricbeat/autodiscover/appender/kubernetes/token
go test -v ./metricbeat/autodiscover/builder/hints

Before the fix:

❯ go test -v .
ok  	github.com/elastic/beats/v7/filebeat/autodiscover/builder/hints	0.530s

After the fix

❯ go test -v .
=== RUN   TestUnpackCopiesDefault
--- PASS: TestUnpackCopiesDefault (0.00s)
=== RUN   TestGenerateHints
--- PASS: TestGenerateHints (0.01s)
=== RUN   TestGenerateHintsWithPaths
--- PASS: TestGenerateHintsWithPaths (0.00s)
PASS
ok  	github.com/elastic/beats/v7/filebeat/autodiscover/builder/hints	0.172s

Related issues

• N/A

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This is an automatic backport of pull request #41891 done by [Mergify](https://mergify.com).

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