Allow rerun of flaky test cases

[Garados007]

Some test cases can fail from time to time and only need to be rerun some times to succeed.

Close #164

[Garados007]

@t-b @MichaelHuth Ready for review.

[t-b]

Review:

Nice addition, works mostly!

• [x] Can we have some more tests with multi data and mulit multi data?

I've tried with

Function/WAVE GetWaveA()

    Make/FREE wv = {100, 200}

    return wv
End

Function/WAVE GetWaveB()

    Make/FREE/T wv = {"a", "b"}

    return wv
End

// IUTF_RETRY_FAILED
// IUTF_TD_GENERATOR v0:GetWaveA
// IUTF_TD_GENERATOR s0:GetWaveB
static Function UnreliableStatus([STRUCT IUTF_mData &m])
    NVAR counter = root:retryCounter
    counter += 1
    CHECK_GE_VAR(counter, 5)

    print m.v0, m.s0
End

which works.

• [x] Can we document the behaviour for multi and multi-multi test cases? I think the current behaviour of not incrementing the dgenIndex on retry is good, but that needs to be written down. @MichaelHuth Please chim in if you object.
• [x] Can we make it work with REQUIRE as well?
• [x] CHECK(counter >= 5) -> CHECK_GE_VAR(counter, 5)
• [x] Can you check in the tests that test case begin/end hooks are executed once per retry?

[Garados007]

Applied the requested changes.

Can we make it work with REQUIRE as well?

Yes. I have added the support for this. It was a bit tricky as failed REQUIREs works differently from a failed CHECK as it aborts the execution right away. I made the support for rerunning failed REQUIREs optionally as there are other conditions that could abort the test case. I updated the documentation and recommend the use of CHECKs for flaky conditions.