Faster locking on .NET 9.0+ using System.Threading.Lock

[MarkCiliaVincenti]

No description provided.

[alex-jitbit]

Thanks for contributing! Have you run the benchmarks before/after?

[MarkCiliaVincenti]

Hi, only on https://github.com/MarkCiliaVincenti/Backport.System.Threading.Lock/tree/master/Backport.System.Threading.Lock.Benchmarks

If you test your current benchmarks you should see no difference, but if you change your target framework to net9 and test both versions you should notice a minor improvement. But it's mostly theoretical since it's on EvictExpired.