Replace LoadNamedFieldPolymorphic with explicit branches.

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 6716f484779817b89cca34cf416ba6de069ba5f7..c2dd2e415d4c61a81455312b0ea9bcd16cac22ab 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -127,7 +127,6 @@ class LCodeGen;
   V(LoadKeyed)                                  \
   V(LoadKeyedGeneric)                           \
   V(LoadNamedField)                             \
-  V(LoadNamedFieldPolymorphic)                  \
   V(LoadNamedGeneric)                           \
   V(MapEnumLength)                              \
   V(MathAbs)                                    \
@@ -1464,19 +1463,6 @@ class LLoadNamedField: public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LLoadNamedFieldPolymorphic: public LTemplateInstruction<1, 1, 0> {
- public:
-  explicit LLoadNamedFieldPolymorphic(LOperand* object) {
-    inputs_[0] = object;
-  }
-
-  DECLARE_CONCRETE_INSTRUCTION(LoadNamedField, "load-named-field-polymorphic")
-  DECLARE_HYDROGEN_ACCESSOR(LoadNamedFieldPolymorphic)
-
-  LOperand* object() { return inputs_[0]; }
-};
-
-
 class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedGeneric(LOperand* object) {