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

src/compiler/js-context-specialization.cc

Index: src/compiler/js-context-specialization.cc
diff --git a/src/compiler/js-context-specialization.cc b/src/compiler/js-context-specialization.cc
index 07746fa98bbed622c4e363a6eedd78703041035b..66780c2ac3834a1c829917c100236cf3e065d7c2 100644
--- a/src/compiler/js-context-specialization.cc
+++ b/src/compiler/js-context-specialization.cc
@@ -35,8 +35,7 @@ MaybeHandle<Context> JSContextSpecialization::GetSpecializationContext(
   Node* const object = NodeProperties::GetValueInput(node, 0);
   switch (object->opcode()) {
     case IrOpcode::kHeapConstant:
-      return Handle<Context>::cast(
-          OpParameter<Unique<HeapObject>>(object).handle());
+      return Handle<Context>::cast(OpParameter<Handle<HeapObject>>(object));
     case IrOpcode::kParameter: {
       Node* const start = NodeProperties::GetValueInput(object, 0);
       DCHECK_EQ(IrOpcode::kStart, start->opcode());