Port random hashing to CoreRT

[InternalHashSortKey](https://github.com/dotnet/corert/blob/master/src/System.Private.CoreLib/src/System/Globalization/CompareInfo.Unix.cs#L353) implementation would need to create secure random hash. See [COMNlsHashProvider::HashSortKey](https://github.com/dotnet/coreclr/blob/master/src/vm/comutilnative.cpp#L2972) for how it's implemented on CoreCLR. 

