swift234

Reflection: Eliminate NominalTypeTrait::setParent()

When creating a TypeRef from metadata, we have a parent pointer
handy, and construct the TypeRef directly, so there's no need
to mutate the TypeRef after the fact.

When demangling a TypeRef from a string, the mangling encodes
the parent module or type context, so we can set it when
constructing the TypeRef there too.