{prefix,partial}Schedule: do not include mapping filters

There are three main use cases of these schedules
- the schedule stored in PromotionInfo is only used during AST generation
  after any outer mapping has already been taken into account,
  so it does not need to store the mapping itself
- scoped accesses are relative to the outer schedule dimensions,
  so they do not need to specifically take into account
  any outer mapping
- unrolling explicitly takes into account the mapping

Author: Sven Verdoolaege

tc/core/polyhedral/schedule_transforms.cc

@@ -55,7 +55,7 @@ isl::union_map extendSchedule(
       schedule =
           schedule.flat_range_product(isl::union_map::from(bandElem->mupa_));
     }
-  } else if (auto filterElem = node->elemAsBase<ScheduleTreeElemFilter>()) {
+  } else if (auto filterElem = node->elemAs<ScheduleTreeElemFilter>()) {
     schedule = schedule.intersect_domain(filterElem->filter_);
   } else if (auto extensionElem = node->elemAs<ScheduleTreeElemExtension>()) {
     // FIXME: we may need to restrict the range of reversed extension map to