isl_map_range: correctly handle maps with 0D domains
isl_map_range: correctly handle maps with 0D domains

Internally, sets are represented as maps with unnamed, unstructured
0D domains.  isl_map_range takes advantage of this fact, but only
checked for 0D domains.  This was correct when isl_map_range was added,
but it should have been updated when named and structured spaces were
introduced.

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

VanirLLVM/toolchain_isl,UBERTC/isl,pierrotdelalune/isl,jleben/isl,BobSaget-Mod/libisl,epowers/isl,jleben/isl,nicolasvasilache/isl,SaberMod/isl-current,serge-sans-paille/isl,BobSaget-Mod/libisl,BenzoSM/isl,pierrotdelalune/isl,nicolasvasilache/isl,Distrotech/isl,UBERTC/isl,evaautomation/isl,tobig/isl,inducer/isl-mirror,SaberMod/isl-current,abduld/isl,epowers/isl,cfx-next/toolchain_isl-upstream,Meinersbur/isl,cfx-next/toolchain_isl-upstream,PollyLabs/isl,epowers/isl,UBERTC/isl,PollyLabs/isl,BobSaget-Mod/libisl,BenzoSM/isl,simbuerg/isl,serge-sans-paille/isl,crossbuild/isl,KangDroidSMProject/ISL,pierrotdelalune/isl,nicolasvasilache/isl,BenzoSM/isl,inducer/isl-mirror,inducer/isl-mirror,Meinersbur/isl,UBERTC/isl,simbuerg/isl,VanirLLVM/toolchain_isl,epowers/isl,epowers/isl,Distrotech/isl,Meinersbur/isl,KangDroidSMProject/ISL,nicolasvasilache/isl,inducer/isl-mirror,pierrotdelalune/isl,evaautomation/isl,cfx-next/toolchain_isl-upstream,pierrotdelalune/isl,KangDroidSMProject/ISL,serge-sans-paille/isl,VanirLLVM/toolchain_isl,SaberMod/isl-current,serge-sans-paille/isl,PollyLabs/isl,BobSaget-Mod/libisl,VanirLLVM/toolchain_isl,KangDroidSMProject/ISL,crossbuild/isl,abduld/isl,VanirLLVM/toolchain_isl,BobSaget-Mod/libisl,Distrotech/isl,simbuerg/isl,abduld/isl,jleben/isl,Distrotech/isl,Meinersbur/isl,tobig/isl,crossbuild/isl,PollyLabs/isl,evaautomation/isl,simbuerg/isl,nicolasvasilache/isl,cfx-next/toolchain_isl-upstream,jleben/isl,abduld/isl,BenzoSM/isl,evaautomation/isl,PollyLabs/isl,simbuerg/isl,inducer/isl-mirror,serge-sans-paille/isl,BenzoSM/isl,crossbuild/isl,jleben/isl,SaberMod/isl-current,tobig/isl,tobig/isl,Distrotech/isl,KangDroidSMProject/ISL,cfx-next/toolchain_isl-upstream