swift234

Sema: Remove redundant mapType{Into,OutOf}Context() calls

The code in recordTypeWitness() seemed to be completely bogus;
it already receives a type written in terms of the archetypes
of the adoptee's context, so mapTypeOutOfContext() did nothing
here, because it was using the wrong substitutions.

The logic for synthesizing designated initializers was also
slightly wrong if the class was nested inside a generic
function.

Finally, interface and contextual types of a derived rawValue
were flipped around.