Add lithium support for %_GetCachedArrayIndex for IA32 and X64

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
===================================================================
--- src/x64/lithium-x64.h	(revision 7028)
+++ src/x64/lithium-x64.h	(working copy)
@@ -89,6 +89,7 @@
   V(DoubleToI)                                  \
   V(FunctionLiteral)                            \
   V(Gap)                                        \
+  V(GetCachedArrayIndex)                        \
   V(GlobalObject)                               \
   V(GlobalReceiver)                             \
   V(Goto)                                       \
@@ -730,6 +731,17 @@
 };
 
 
+class LGetCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
+ public:
+  explicit LGetCachedArrayIndex(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(GetCachedArrayIndex, "get-cached-array-index")
+  DECLARE_HYDROGEN_ACCESSOR(GetCachedArrayIndex)
+};
+
+
 class LHasCachedArrayIndex: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LHasCachedArrayIndex(LOperand* value) {