Update Xunit version, migrate FSharpSuite.Tests to Xunit

[majocha]

Updates Xunit to 2.9.0.

Migrate FSharpSuite.Tests to Xunit (But the parallelization is still disabled).

In line with:
#13654
#9947

[github-actions]

✅ No release notes required

[majocha]

@psfinaki this surprisingly worked.

I'm not sure, is it ok to upgrade the Xunit version? The one we are on currently is seriously old.

[psfinaki]

This is brilliant, Jakub, brilliant, thanks for doing this! 🚀 🚀 🚀

Regarding xunit update, that's also definitely a good thing :)

[psfinaki]

Wait @majocha, just for my understanding, did you jump on this because I was recently crying for help on this topic at this meetup? :D

[majocha]

@psfinaki I might have been somewhat influenced by the video xD.

[psfinaki]

Ohhh... There I promised to visit that person in their city and buy them a beer 🤔 Okay I will reach out to you offline once we merge this :D

[psfinaki]

Awesome job :)

It's really a surprise this worked out without bigger hiccups, such a surprise that I manually checked that tests execute and pass in the CI but yeah they do :D

[vzarytovskii]

Hm, so

This PR: 72,238
Previous run in main: 72,998

@majocha from the top of your head, do you know why it's around 600 tests less reported?

[T-Gro]

https://dev.azure.com/dnceng-public/public/_build/results?buildId=796072&view=logs&j=916a2273-64f0-5130-a29e-a4d2f7e48c60&t=b833feec-4728-51e1-390e-168ead0990a4&l=119538

  "D:\a\_work\1\s\tests\fsharp\FSharpSuite.Tests.fsproj" (VSTest target) (1) ->
   (_VSTestMSBuild target) ->
     D:\a\_work\1\s\.dotnet\sdk\9.0.100-preview.7.24407.12\Microsoft.TestPlatform.targets(46,5): warning : [xUnit.net 00:00:00.72] Skipping: FSharpSuite.Tests (could not load dependent assembly 'FSharpSuite.Tests, Version=12.9.100'): Could not load file or assembly 'FSharpSuite.Tests, Version=12.9.100.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. Strong name signature could not be verified.  The assembly may have been tampered with, or it was delay signed but not fully signed with the correct private key. (Exception from HRESULT: 0x80131045) [D:\a\_work\1\s\tests\fsharp\FSharpSuite.Tests.fsproj::TargetFramework=net472]
     D:\a\_work\1\s\.dotnet\sdk\9.0.100-preview.7.24407.12\Microsoft.TestPlatform.targets(46,5): warning : No test is available in D:\a\_work\1\s\artifacts\bin\FSharpSuite.Tests\Release\net472\FSharpSuite.Tests.dll. Make sure that test discoverer & executors are registered and platform & framework version settings are appropriate and try again. [D:\a\_work\1\s\tests\fsharp\FSharpSuite.Tests.fsproj::TargetFramework=net472]

[majocha]

@vzarytovskii by the number it is about one entire target of FSharpSuite not running.

[psfinaki]

This might be because the xunit runner is not configured, I am checking this locally

[majocha]

Yes, there is no xunit.runner.json.

[psfinaki]

Trying this out here: #17658

[majocha]

possibly something like this dotnet/arcade#14091