Potential broken recursion in CompilerGeneratedState

There's a potential recursion in the `CompilerGeneratedState` which could lead to stack overflow.

Populating the cache for a type in `PopulateCacheForType` may end up producing warnings, for example here:
https://github.com/dotnet/linker/blob/17033869c8e75e3805ba42af4c5509af72c8bb72/src/linker/Linker/CompilerGeneratedState.cs#L176

But the logging infra will go check for warning suppressions which will end up calling `CompilerGeneratedState.TryGetOwningMethodForCompilerGeneratedMember` which can call back to `PopulateCacheForType`:
https://github.com/dotnet/linker/blob/17033869c8e75e3805ba42af4c5509af72c8bb72/src/linker/Linker/CompilerGeneratedState.cs#L404

If this happens on the same type, it could lead to endless recursion.

I didn't try to come up with a repro as it probably involves handcrafting IL...