[turbofan] Add support for accessing Uint8ClampedArrays.

src/compiler/simplified-lowering.h

Index: src/compiler/simplified-lowering.h
diff --git a/src/compiler/simplified-lowering.h b/src/compiler/simplified-lowering.h
index 9e2a499bc6f6404ad7120e53d816529b4df2f053..09e58ff18a17c17d788aa965feca4e9e21dcba23 100644
--- a/src/compiler/simplified-lowering.h
+++ b/src/compiler/simplified-lowering.h
@@ -44,6 +44,10 @@ class SimplifiedLowering final {
   void DoIntegral32ToBit(Node* node);
   void DoOrderedNumberToBit(Node* node);
   void DoNumberToBit(Node* node);
+  void DoIntegerToUint8Clamped(Node* node);
+  void DoNumberToUint8Clamped(Node* node);
+  void DoSigned32ToUint8Clamped(Node* node);
+  void DoUnsigned32ToUint8Clamped(Node* node);
 
  private:
   JSGraph* const jsgraph_;