Revert r4782. Fix issues 728, 732.

src/ia32/ic-ia32.cc

Index: src/ia32/ic-ia32.cc
diff --git a/src/ia32/ic-ia32.cc b/src/ia32/ic-ia32.cc
index 3aa60baa74c38d5e54a62d5632eef44e9c631a84..2a085984e18b4a386b0d703529c53d25f9df0b6f 100644
--- a/src/ia32/ic-ia32.cc
+++ b/src/ia32/ic-ia32.cc
@@ -404,8 +404,8 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   __ j(above_equal, &slow);
   // Is the string an array index, with cached numeric value?
   __ mov(ebx, FieldOperand(eax, String::kHashFieldOffset));
-  __ test(ebx, Immediate(String::kIsArrayIndexMask));
-  __ j(not_zero, &index_string, not_taken);
+  __ test(ebx, Immediate(String::kContainsCachedArrayIndexMask));
+  __ j(zero, &index_string, not_taken);
 
   // Is the string a symbol?
   // ecx: key map.