Align implementation of DCS, XMLSerializer and JSON serializer with .NET framework

[HongGit]

During investigation of serialization bugs, it is found that the implementation of DCS, XMLSerializer and JSON serializer is quite different from .NET framework.

• DCJS - Semi-aligned by Align DCJS with 4.8 implementation. #57533.
• DCS and the rest of the DataContract world was aligned with DCS alignment to 4.8 with schema support #71752.
• XmlSerializer - Yet todo.

[danmoseley]

@HongGit I assume this should be marked Future or 6.0