[m-rev.] for post-commit review: expand and pack in one pass, step 1

[Peter Wang]

On Mon, 05 Mar 2018 16:46:58 +1100 (AEDT), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> Do expansion and packing in the same pass.
> 
> compiler/ml_unify_gen.m:
>     Expand double-word args and pack sub-word arguments in the same pass,
>     initially for dynamically constructed cells only.
> 
>     Doing both in the same pass is a prerequisite for future improvements
>     in argument packing schemes.
> 
> tests/hard_coded/packed_arg_partial_inst.{m,exp}:
>     A new test case to test the packing of arguments when some of them
>     have inst "free".
> 
> tests/hard_coded/Mmakefile:
>     Enable the new test case.
> 

That's fine.

Peter