[m-rev.] for review: Fix inst for constant type_infos.

[Julien Fischer]

On Tue, 3 Sep 2013, Peter Wang wrote:

> The inst for type_infos entered into the const_struct database did not
> count the type_ctor_info argument, thus the cons_id arity was off by one.
> Bug #297.
>
> compiler/polymorphism.m:
>        Account for the type_ctor_info when making the inst for a constant
>        type_info.
>
> tests/hard_coded/Mercury.options:
> tests/hard_coded/Mmakefile:
> tests/hard_coded/type_info_const_inst.exp:
> tests/hard_coded/type_info_const_inst.m:
>        Add test case.

That looks fine.  Could you please also add an entry the NEWS file for
13.05.2 saying that bug #297 has been fixed.

Cheers,
Julien.