isl_convex_hull.c: remove dead code
isl_convex_hull.c: remove dead code

The removed code would handle 0D polytopes, but they have
been handled already a couple of lines up and there is no
way for the dimension to change between the two tests.

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