remove_all_equalities: also remove parameter equalities after main compression

remove_all_equalities: also remove parameter equalities after main compression

Commit barvinok-0.25-14-ge52f4ac65c (remove_all_equalities: keep
removing equalities until no new ones are created,
Sat Oct 20 13:56:16 2007 +0200) ensured parameter equality constraints
detected as a result of variable compression on the context
got removed as well.
Commit barvinok-0.26-20-g0d0f130c86 (remove_all_equalities: keep
removing parameter equalities until none left,
Wed Mar 12 15:38:39 2008 +0100) ensured those detected as a result
of parameter compression on the main polyhedron got removed.
However, the variable compression on the main polyhedron
may also uncover equality constraints on the parameters.
Remove those too.

Reported-by: Corentin Ferry <corentin.ferry@irisa.fr>
Signed-off-by: Sven Verdoolaege <sven.verdoolaege@gmail.com>