Migrate SonarAnalyzer.UnitTest project target framewrok from net7.0 to net8.0

[sebastien-marichal]

• Revert this changes: Fix UTs caused by .NET 8 release by using specific nuget version #8362
• Update SonarAnalyzer.UnitTest target frameworks from net48;net7.0 to net48;net8.0
• Move tests from SonarAnalyzer.Net8.UnitTest to SonarAnalyzer.UnitTest
• Remove SonarAnalyzer.Net8.UnitTest

This migration needs to ensure that all Razor unit tests work as expected. We had issues in the past when starting to use .NET 8 preview, and those tests started failing.

[andrei-epure-sonarsource]

Hey @sebastien-marichal - could you please sync with @costin-zaharia-sonarsource on what we want to do?

It seems that this ticket suggest removing the Net8.UnitTest, and this comment says that we should not remove it.

What is said inside an issue takes precedence over what is said only in a comment, but I'd still like a common understanding.

I would like to have a clear plan at squad level.

Thanks!

[costin-zaharia-sonarsource]

@andrei-epure-sonarsource, @sebastien-marichal

In my opinion, we should do the following:

• extract the "test framework" logic in a separate project that can be reused: Update test framework: extract the Verifier, VerifierBuilder + extensions and ParseOptionsHelper in own project #8237
• move the net8 unit tests to the default unit test project and update it to target .net 8 (this issue)
• move all the razor-related tests to a dedicated project -> this will better isolate them and will allow us to avoid the issues we had with unpublished Nuget packages (MSBuildWorkspace doesn't raise warnings or errors if the app is targeting too low of a version of Roslyn dotnet/roslyn#69578 (comment))

[costin-zaharia-sonarsource]

Closing this as done.

[costin-zaharia-sonarsource]

We still need to do the revert.

[pavel-mikula-sonarsource]

@costin-zaharia-sonarsource Can we close this now?

[costin-zaharia-sonarsource]

Yes 🥳