add original schedule to scop

add original schedule to scop

    * graphite-optimize-isl.c (optimize_isl): Call isl_union_map_is_equal.
    * graphite-poly.c (new_scop): Initialize original_schedule.
    (free_scop): Free original_schedule.
    * graphite-poly.h (struct scop): Add field original_schedule.
    * graphite-sese-to-poly.c (build_scop_original_schedule): New.
    (build_poly_scop): Call build_scop_original_schedule.

From-SVN: r229910