isl_flow.c: use public isl_vec interface
isl_flow.c: use public isl_vec interface

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

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