Add tests for DataContractSerializer serializing System.Globalization types

We need have tests covering DataContractSerializer serializing the following types.
Refer https://github.com/dotnet/corefx/blob/master/src/System.Runtime.Serialization.Xml/tests/DataContractSerializer.cs on how to add the DCS tests using the common helper method.
dotnet/runtime#21982

- [ ] System.Globalization.CompareInfo
- [ ] System.Globalization.SortVersion