* Porting Hidden and HiddenFor unit tests

Partial fix to #453
We have code with foo, bar, baz for quite some time and they work with Policheck: https://github.com/aspnet/Mvc/blob/0d8a7368d941b8d20c0de1e6de831737c6293d52/test/Microsoft.AspNet.Mvc.HeaderValueAbstractions.Test/MediaTypeHeaderValueParsingTests.cs