[turbofan] Turn LoadElimination into an AdvancedReducer.

test/unittests/compiler/load-elimination-unittest.cc

Index: test/unittests/compiler/load-elimination-unittest.cc
diff --git a/test/unittests/compiler/load-elimination-unittest.cc b/test/unittests/compiler/load-elimination-unittest.cc
index 52c3143e2aebe78caa4f8728f3170e51618b0ed2..3ad11cf43fd924a5d6f514bc5503f7184fc626b4 100644
--- a/test/unittests/compiler/load-elimination-unittest.cc
+++ b/test/unittests/compiler/load-elimination-unittest.cc
@@ -19,7 +19,9 @@ class LoadEliminationTest : public GraphTest {
 
  protected:
   Reduction Reduce(Node* node) {
-    LoadElimination reducer;
+    // TODO(titzer): mock the GraphReducer here for better unit testing.
+    GraphReducer graph_reducer(zone(), graph());
+    LoadElimination reducer(&graph_reducer);
     return reducer.Reduce(node);
   }