Backport.System.Threading.Lock implementation.

[MarkCiliaVincenti]

For some reason I couldn't build this project on my machine, not even the main branch; loads of analyzer errors, so please ensure the changes are applied well.

[MarkCiliaVincenti]

I also changed LangVersion from preview to latest. You may or may want to revert this; if you added it for the System.Threading.Lock functionality, it's not needed anymore since .NET 9.0 was released.

[thomhurst]

Doesn't compile unfortunately:

error CS0052: Inconsistent accessibility: field type 'Lock' is less accessible than field 'TestContext.Lock' [/home/runner/work/TUnit/TUnit/TUnit.Core/TUnit.Core.csproj::TargetFramework=net8.0]

[MarkCiliaVincenti]

Try now please @thomhurst?

[thomhurst]

We're now changing the API and making the lock non-public

[MarkCiliaVincenti]

OK in this case I'll revert this particular lock then.

[MarkCiliaVincenti]

Reverted that part @thomhurst

[MarkCiliaVincenti]

I reverted back the LangVersion to preview.

[MarkCiliaVincenti]

Oops, missed a few LangVersion reverts.

[thomhurst]

Looks like you're actually changing most latest lang versions to preview now

[MarkCiliaVincenti]

Looks like you're actually changing most latest lang versions to preview now

Yes I missed a few. You could move them to latest but you'd need to fix the pipelines so they compile with the latest SDK of .NET 9.0

[MarkCiliaVincenti]

All OK now?

[MarkCiliaVincenti]

@thomhurst not quite sure what this error relates to now, but likely unrelated to this PR.

[thomhurst]

Thanks @MarkCiliaVincenti !