Backport r5553 "Do not invoke indexed interceptor getters for negative indice...

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
===================================================================
--- src/x64/ic-x64.cc	(revision 5553)
+++ src/x64/ic-x64.cc	(working copy)
@@ -683,8 +683,8 @@
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(rcx, &slow);
 
-  // Check that the key is a smi.
-  __ JumpIfNotSmi(rax, &slow);
+  // Check that the key is an array index, that is Uint32.
+  __ JumpIfNotPositiveSmi(rax, &slow);
 
   // Get the map of the receiver.
   __ movq(rdx, FieldOperand(rcx, HeapObject::kMapOffset));