isl_{set,map}_dup: copy subsets instead of duping them
isl_{set,map}_dup: copy subsets instead of duping them

If the subsets are going to be changed, they will be
duped anyway later and otherwise it is a waste to dup them.

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