isl_map_normalize: extract out sort_and_remove_duplicates
isl_map_normalize: extract out sort_and_remove_duplicates

We will be able to reuse this function in the next commit.

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

simbuerg/isl,inducer/isl-mirror,crossbuild/isl,simbuerg/isl,UBERTC/isl,tobig/isl,KangDroidSMProject/ISL,abduld/isl,Distrotech/isl,Distrotech/isl,Meinersbur/isl,inducer/isl-mirror,abduld/isl,nicolasvasilache/isl,crossbuild/isl,BenzoSM/isl,PollyLabs/isl,crossbuild/isl,PollyLabs/isl,PollyLabs/isl,PollyLabs/isl,KangDroidSMProject/ISL,Meinersbur/isl,Meinersbur/isl,KangDroidSMProject/ISL,nicolasvasilache/isl,crossbuild/isl,evaautomation/isl,SaberMod/isl-current,evaautomation/isl,SaberMod/isl-current,Distrotech/isl,jleben/isl,UBERTC/isl,SaberMod/isl-current,simbuerg/isl,tobig/isl,abduld/isl,abduld/isl,BenzoSM/isl,inducer/isl-mirror,jleben/isl,KangDroidSMProject/ISL,Distrotech/isl,KangDroidSMProject/ISL,SaberMod/isl-current,UBERTC/isl,Distrotech/isl,BenzoSM/isl,Meinersbur/isl,simbuerg/isl,nicolasvasilache/isl,BenzoSM/isl,jleben/isl,tobig/isl,UBERTC/isl,tobig/isl,nicolasvasilache/isl,inducer/isl-mirror,simbuerg/isl,evaautomation/isl,evaautomation/isl,PollyLabs/isl,nicolasvasilache/isl,BenzoSM/isl,jleben/isl,inducer/isl-mirror,jleben/isl