Remove HFixedArrayBaseLength instruction and replace with regular HLoadNamedField.

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 d6edd6de8bd92f7a75d02f267f9933404d3ffcb8..a7530be14ee1b2dab38d358506b4bfa007b63097 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -99,7 +99,6 @@ class LCodeGen;
   V(DoubleToSmi)                                \
   V(DummyUse)                                   \
   V(ElementsKind)                               \
-  V(FixedArrayBaseLength)                       \
   V(MapEnumLength)                              \
   V(FunctionLiteral)                            \
   V(GetCachedArrayIndex)                        \
@@ -1233,20 +1232,6 @@ class LCmpMapAndBranch: public LControlInstruction<1, 0> {
 };
 
 
-class LFixedArrayBaseLength: public LTemplateInstruction<1, 1, 0> {
- public:
-  explicit LFixedArrayBaseLength(LOperand* value) {
-    inputs_[0] = value;
-  }
-
-  LOperand* value() { return inputs_[0]; }
-
-  DECLARE_CONCRETE_INSTRUCTION(FixedArrayBaseLength,
-                               "fixed-array-base-length")
-  DECLARE_HYDROGEN_ACCESSOR(FixedArrayBaseLength)
-};
-
-
 class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LMapEnumLength(LOperand* value) {