Fix one more cast warning on Win32

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index a30f808b489f1d59ca6369e151e5c22d41fc6476..3629a402abc1aa58ec0650feea14aabb80010bba 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -648,7 +648,7 @@ Condition MacroAssembler::IsObjectNameType(Register heap_object,
                                            Register instance_type) {
   mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
   movzx_b(instance_type, FieldOperand(map, Map::kInstanceTypeOffset));
-  cmpb(instance_type, static_cast<int8_t>(LAST_NAME_TYPE));
+  cmpb(instance_type, static_cast<uint8_t>(LAST_NAME_TYPE));
   return below_equal;
 }