Consider replacing CoreCompileCache with Roslyn DeterministicKey

Roslyn is considering exposing an API to compute a key that describes the inputs to a compilation (dotnet/roslyn#57162).

That could be used to replace the CoreCompileCache concept in Common.targets:

https://github.com/dotnet/msbuild/blob/7434b575d12157ef98aeaad3b86c8f235f551c41/src/Tasks/Microsoft.Common.CurrentVersion.targets#L3643-L3673

That was introduced to avoid problems with the Compile list changing between runs (#1328).

However, if Roslyn exposed a task with similar API to the `Csc`/`Vbc` tasks that returned (something like) the DeterministicKey instead of doing compilation, we could use that output instead (instead of having to follow the `CoreCompile` inputs as in #5334).

This came up when @RikkiGibson and I were talking about some stuff.