[turbofan] Remove usage of Unique<T> from graph.

test/cctest/compiler/graph-builder-tester.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_CCTEST_COMPILER_GRAPH_BUILDER_TESTER_H_
 #define V8_CCTEST_COMPILER_GRAPH_BUILDER_TESTER_H_
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 
@@ skipping 86 matching lines @@
 
   Node* PointerConstant(void* value) {
     intptr_t intptr_value = reinterpret_cast<intptr_t>(value);
     return kPointerSize == 8 ? NewNode(common()->Int64Constant(intptr_value))
                              : Int32Constant(static_cast<int>(intptr_value));
   }
   Node* Int32Constant(int32_t value) {
     return NewNode(common()->Int32Constant(value));
   }
   Node* HeapConstant(Handle<HeapObject> object) {
-    Unique<HeapObject> val = Unique<HeapObject>::CreateUninitialized(object);
-    return NewNode(common()->HeapConstant(val));
+    return NewNode(common()->HeapConstant(object));
   }
 
   Node* BooleanNot(Node* a) { return NewNode(simplified()->BooleanNot(), a); }
 
   Node* NumberEqual(Node* a, Node* b) {
     return NewNode(simplified()->NumberEqual(), a, b);
   }
   Node* NumberLessThan(Node* a, Node* b) {
     return NewNode(simplified()->NumberLessThan(), a, b);
   }
@@ skipping 180 matching lines @@
   Node* return_;
   Node** parameters_;
   MaybeHandle<Code> code_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_COMPILER_GRAPH_BUILDER_TESTER_H_