conformance: add Hook in ConformanceTestSuite

[zirain]

What type of PR is this?

/kind feature
/kind test
/area conformance-test

What this PR does / why we need it:

Add hook points support in conformance test suite

Which issue(s) this PR fixes:

Fixes #3131

Does this PR introduce a user-facing change?:

Add hook points support in conformance test suite

[arkodg]

/approve thanks !

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: arkodg, zirain

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• conformance/OWNERS [arkodg]

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[youngnick]

I think this is okay, as it only runs after the test has been completed. It's super important that we don't allow hooks before, as we don't want the behavior of the conformance tests to be able to be modified (or else we can't be sure that the same behavior is executed for every implementation, defeating the point of conformance).

I won't LGTM though, as I'd like @mlavacca to confirm he's okay with this. Holding for his review.

/hold

[zirain]

I want to clearify that, we want this to run dump function for debugging a flaky test.
That's why this was only added to post-test.