Remove support for smi-based keyed accesses on 64bit.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 786ff87afe261757b76911df89989b9473baddb9..bf59159164c53b4e41ae52ee2d48d76625017a1b 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -5885,8 +5885,8 @@ class ArrayInstructionInterface {
   virtual ~ArrayInstructionInterface() { };
 
   static Representation KeyedAccessIndexRequirement(Representation r) {
-    return r.IsInteger32() ? Representation::Integer32()
-                           : Representation::Smi();
+    return r.IsInteger32() || kSmiValueSize != 31
+        ? Representation::Integer32() : Representation::Smi();
   }
 };