isl_union_map: ignore parameters when looking up entries
isl_union_map: ignore parameters when looking up entries

That is, once an entry has been found with the right (tuple) hash value,
ignore the parameters when checking whether the hash values correspond
to the same space.
This complements the move to using the tuple hash in the hash table and
is valid for the same reason.
With both changes in, look-ups can be performed
without first aligning parameters.

Signed-off-by: Sven Verdoolaege <235c10dd23b819f81cdc9756a251746bc184cab6@gmail.com>

Meinersbur/isl,Meinersbur/isl,Meinersbur/isl,Meinersbur/isl