Why does MakeElementStack() have to use ToTypedElementLegacy()

[ewoutkramer]

When serializing to xml, with or without xxxxLegacy, the output looks the same, only the Legacy version has more whitespace (which is what the unit test is testing). But what does whitespace have to do with ToTypedElement()??? It is true we need to support the Pretty stuff on the new XML serializers, but I don't see that it makes a difference here.

Anyway, if we don't use xxxLegacy, DoesPretty and TestAppendNewLine fails.