Add complete ElementKind information directly to Map for objects with elements.

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
diff --git a/src/x64/ic-x64.cc b/src/x64/ic-x64.cc
index 8f4f9f98b5d4e1c15cccb528b7b6a427401900b8..8d74500d2fe79c620431e22139a1c215cc152240 100644
--- a/src/x64/ic-x64.cc
+++ b/src/x64/ic-x64.cc
@@ -510,9 +510,7 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
 
   // Check the "has fast elements" bit in the receiver's map which is
   // now in rcx.
-  __ testb(FieldOperand(rcx, Map::kBitField2Offset),
-           Immediate(1 << Map::kHasFastElements));
-  __ j(zero, &check_number_dictionary);
+  __ CheckFastElements(rcx, &check_number_dictionary);
 
   GenerateFastArrayLoad(masm,
                         rdx,