isl_map.c: basic_map_space_reset: handle NULL input
isl_map.c: basic_map_space_reset: handle NULL input

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

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