[turbofan] Remove RepresentationChanger::simplified field.

test/cctest/compiler/test-representation-change.cc

Index: test/cctest/compiler/test-representation-change.cc
diff --git a/test/cctest/compiler/test-representation-change.cc b/test/cctest/compiler/test-representation-change.cc
index 60972243a079ab4045472259caa4d0570c9e4242..80973e41659200809a6013325b814ce3ad7abd86 100644
--- a/test/cctest/compiler/test-representation-change.cc
+++ b/test/cctest/compiler/test-representation-change.cc
@@ -27,8 +27,8 @@ class RepresentationChangerTester : public HandleAndZoneScope,
       : GraphAndBuilders(main_zone()),
         javascript_(main_zone()),
         jsgraph_(main_isolate(), main_graph_, &main_common_, &javascript_,
-                 nullptr, &main_machine_),
-        changer_(&jsgraph_, &main_simplified_, main_isolate()) {
+                 &main_simplified_, &main_machine_),
+        changer_(&jsgraph_, main_isolate()) {
     Node* s = graph()->NewNode(common()->Start(num_parameters));
     graph()->SetStart(s);
   }