Ideally we'd just do this when we need it, but the ostream derivation
will be controlled by both global config and per-structure config, so
it's hard to know exactly when we need it and when we don't.
* Emit struct literal with list-initializer when language is Cxx
* Update test results
* Add test case - struct literal order
* Memoize struct field names
* Specify struct type at front of initializer