[m-rev.] for review: Make qualify_cons_id not return cons_ids containing dummy type_ctor.

[Zoltan Somogyi]

On Thu,  6 May 2021 13:46:15 +1000, Peter Wang <novalazy at gmail.com> wrote:
> compiler/prog_type.m:
>     Make qualify_cons_id return the same cons_id for types and insts,
>     with the type_ctor field set correctly instead of a dummy type_ctor.
>     The old behaviour was the source of cons_ids in insts with dummy
>     type_ctor values AFTER post-typecheck.
> 
> compiler/modecheck_coerce.m:
>     Resolve a question related this to fix.

The diff looks ok. Any problems it causes are due to other compiler
modules expecting something they are not supposed to expect.

Zoltan.