rename isl_union_*_has_domain_space to isl_union_*_has_domain_space_tuples
rename isl_union_*_has_domain_space to isl_union_*_has_domain_space_tuples

The new name more accurately reflects that the parameters are ignored.

Signed-off-by: Sven Verdoolaege <dd860110a62b19214c4ee03aec0abffecb4e86b8@cerebras.net>

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