[turbofan] JSTypedLowering can just look at the type hints.

src/compiler/js-typed-lowering.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_JS_TYPED_LOWERING_H_
 #define V8_COMPILER_JS_TYPED_LOWERING_H_
 
 #include "src/base/flags.h"
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/opcodes.h"
@@ skipping 18 matching lines @@
 
 
 // Lowers JS-level operators to simplified operators based on types.
 class JSTypedLowering final : public AdvancedReducer {
  public:
   // Flags that control the mode of operation.
   enum Flag {
     kNoFlags = 0u,
     kDeoptimizationEnabled = 1u << 0,
     kDisableIntegerBinaryOpReduction = 1u << 1,
-    kTypeFeedbackEnabled = 1u << 2,
   };
   typedef base::Flags<Flag> Flags;
 
   JSTypedLowering(Editor* editor, CompilationDependencies* dependencies,
                   Flags flags, JSGraph* jsgraph, Zone* zone);
   ~JSTypedLowering() final {}
 
   Reduction Reduce(Node* node) final;
 
  private:
@@ skipping 63 matching lines @@
   TypeCache const& type_cache_;
 };
 
 DEFINE_OPERATORS_FOR_FLAGS(JSTypedLowering::Flags)
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_TYPED_LOWERING_H_