[Polly] Fix unused variable in non-assert builds. NFC.

GitOrigin-RevId: fa6c5107c369be63c1923632d206e21a932f9870
diff --git a/lib/Transform/ScheduleTreeTransform.cpp b/lib/Transform/ScheduleTreeTransform.cpp
index 08b377c..0a35fc0 100644
--- a/lib/Transform/ScheduleTreeTransform.cpp
+++ b/lib/Transform/ScheduleTreeTransform.cpp
@@ -873,12 +873,10 @@
   bool AnyChange = false;
 
   isl::schedule visitBand(isl::schedule_node_band Band, isl::union_map Deps) {
-    int NumLoops = Band.n_member().release();
-
     // { Domain[] -> Scatter[] }
     isl::union_map PartSched =
         isl::union_map::from(Band.get_partial_schedule());
-    assert(getNumScatterDims(PartSched) == NumLoops);
+    assert(getNumScatterDims(PartSched) == Band.n_member().release());
     isl::space ParamSpace = PartSched.get_space().params();
 
     // { Scatter[] -> Domain[] }