Check if a fatal warning issued in typer is silenced, before converting it into an error

[KacperFKorban]

closes lampepfl#17741
closes lampepfl#17735

[dwijnand]

I have a number of issues with this.

First the premise: I don't see how this is doing anything before converting it to an error, if anything it looks like it's converting warnings to errors before running through Wconf.

Your test doesn't seem to capture the intent of the original 17741 and the issue 17735 doesn't have a test case either. Your 17741 seems to be triggering a auto-apply-insertion warning, which is correctly suppressed by @nowarn. So it's nothing to do with -Wnonunit-statement, which is also missing from the test case anyways.

[KacperFKorban]

Converting warnings to errors before checking -Wconf was a mistake, I fixed it now and added a test to make sure.

This change is supposed to address the fact that when using StoreReporter with fromTyperState = true, issueUnconfigured was called before issueIfNotSuppressed. Because of that, warnings under -Xfatal-warnings were converted to errors before any check for -Wconf or @nowarn was done. (related PR: #13911)

The bug had nothing to do with -Wnonunit-statement or -Wvalue-discard, so I used a simpler test before. I added the tests for i17735 and i17741 now. (Though in i17741, I used a macro-expanded version)

[KacperFKorban]

@dwijnand Have you had some time to read my last comment? (It might have gotten buried in your notifications)