[turbofan] Minor cleanup to reduce code duplication.

test/unittests/compiler/change-lowering-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/code-stubs.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/simplified-operator.h"
 #include "test/unittests/compiler/compiler-test-utils.h"
@@ skipping 43 matching lines @@
   int SmiShiftAmount() const { return kSmiTagSize + SmiShiftSize(); }
   int SmiShiftSize() const {
     return Is32() ? SmiTagging<4>::SmiShiftSize()
                   : SmiTagging<8>::SmiShiftSize();
   }
   int SmiValueSize() const {
     return Is32() ? SmiTagging<4>::SmiValueSize()
                   : SmiTagging<8>::SmiValueSize();
   }
 
-  Node* Parameter(int32_t index = 0) {
-    return graph()->NewNode(common()->Parameter(index), graph()->start());
-  }
-
   Reduction Reduce(Node* node) {
     MachineOperatorBuilder machine(zone(), WordRepresentation());
     JSOperatorBuilder javascript(zone());
     JSGraph jsgraph(graph(), common(), &javascript, &machine);
     CompilationInfo info(isolate(), zone());
     Linkage linkage(zone(), &info);
     ChangeLowering reducer(&jsgraph, &linkage);
     return reducer.Reduce(node);
   }
 
@@ skipping 377 matching lines @@
               IsIfTrue(AllOf(CaptureEq(&branch),
                              IsBranch(IsUint32LessThanOrEqual(
                                           val, IsInt32Constant(SmiMaxValue())),
                                       graph()->start()))),
               AllOf(CaptureEq(&if_false), IsIfFalse(CaptureEq(&branch))))));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8