[m-rev.] for post-commit review: merge MLDS switch arms with identical code

[Peter Wang]

On Tue, 05 Mar 2024 13:53:48 +1100 "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> Merge identical cases in MLDS tag switches.
> 
> compiler/ml_tag_switch.m:
>     If a HLDS switch arm has several cons_ids that differ in what kinds
>     ptags they correspond to (e.g. one may use an unshared primary tag value,
>     one may use a primary tag value shared by several local secondary tags,
>     and one may use a primary tag value shared by several remote secondary
>     tags, then we normally handle them separately. However, it is possible
>     for e.g. *all* the (local or remote) secondary tag values corresponding
>     to a primary tag value to belong to the same HLDS switch arm. In that
>     case, we can merge the MLDS switch case we generate for those cons_ids
>     with the MLDS switch cases of all the other primary tag values that
>     also belong to the same HLDS switch arm. With this diff, we do so.
> 
> compiler/ml_switch_gen.m:
>     Add a comment.

That looks fine. I fixed a couple of typos in comments.

Peter