isl_basic_set_compute_vertices: plug memory leak on error path
isl_basic_set_compute_vertices: plug memory leak on error path

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

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