[turbofan] Remove the useless SimplifiedOperatorReducer.

src/compiler/simplified-operator-reducer.h

-// 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.
-
-#ifndef V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_
-#define V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_
-
-#include "src/compiler/graph-reducer.h"
-#include "src/compiler/simplified-operator.h"
-
-namespace v8 {
-namespace internal {
-
-// Forward declarations.
-class Factory;
-class Heap;
-
-namespace compiler {
-
-// Forward declarations.
-class JSGraph;
-class MachineOperatorBuilder;
-
-class SimplifiedOperatorReducer final : public Reducer {
- public:
-  explicit SimplifiedOperatorReducer(JSGraph* jsgraph);
-  ~SimplifiedOperatorReducer() final;
-
-  Reduction Reduce(Node* node) final;
-
- private:
-  Reduction Change(Node* node, const Operator* op, Node* a);
-  Reduction ReplaceFloat64(double value);
-  Reduction ReplaceInt32(int32_t value);
-  Reduction ReplaceUint32(uint32_t value) {
-    return ReplaceInt32(bit_cast<int32_t>(value));
-  }
-  Reduction ReplaceNumber(double value);
-  Reduction ReplaceNumber(int32_t value);
-
-  Graph* graph() const;
-  Factory* factory() const;
-  JSGraph* jsgraph() const { return jsgraph_; }
-  MachineOperatorBuilder* machine() const;
-  SimplifiedOperatorBuilder* simplified() { return &simplified_; }
-
-  JSGraph* jsgraph_;
-  SimplifiedOperatorBuilder simplified_;
-
-  DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorReducer);
-};
-
-}  // namespace compiler
-}  // namespace internal
-}  // namespace v8
-
-#endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_