Same as the previous few, this just enables copyout for data constructs and ensures we have sufficient test coverage.
stop reporting 'copyin' as not implemented on a data/enter data construct, and enforce sema rules.
This is once again simply enabling this for 'data', 'enter data', and 'exit data' (and ensuring we error for 'host_data'). Implementation is very simply to enable it rather than emit the not-implemented diagnostic.