show summary of retried and flaky tests

[nohwnd]

Summary

When we retried a test, show list of tests that needed to be retried to the user if they specify

--show-retried-tests

When we retried a test and it succeeded, show the list of such tests to the user if they specify

--show-flaky-tests

Background and Motivation

users want to know which tests are potentially flaky, and might want to have easy overview of what tests failed and were retried at least once.

Caveat is that we have folded dynamic tests, and these tests will re-run all tests including tests that prevoiusly passed, so they will appear among flaky tests, and we cannot identify them better because testnodeuid is not unique per such tests, but per the test method that produces multiple results.

[nohwnd]

After looking into this a bit more, this is complicated by the fact that some tests can re-run and always succeed because of how folded tests work. At the same time we don't have enough information about those tests to be able to tell them apart, and link together only results that have the same source data. So some of the tests can pass when, and some other tests with other data can fail, and we don't know which is which.

[nohwnd]

@sharwell I am tracking the ask you had here. I will have to come back to it later, it is not as simple as I thought to make it reliable.

But when we do have a report of the flaky tests, would it still be useful enough if we just print a list of those tests into results? We don't have a category for that in trx format AFAIK, or UI in azdo. And we don't have a new test report format yet, that would be able to communicate this.