real: remove HMMS

Summary:
It doesn't compile and I didn't see any easy way to fix it (I got
stuck at `import Native`, which, according to a comment, comes from
`hbc`). According to another comment,  there were other problems with
the test even when it did compile:
  "HMMS test only works on SPARC machines"

In any case, this has been broken for a while so I don't think anyone
will miss it.

Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Test Plan: run nofib

Reviewers: erikd, bgamari

Reviewed By: bgamari

Differential Revision: https://phabricator.haskell.org/D3088