[turbofan] Address a couple of Type-related TODOs.

src/compiler/js-native-context-specialization.cc

Index: src/compiler/js-native-context-specialization.cc
diff --git a/src/compiler/js-native-context-specialization.cc b/src/compiler/js-native-context-specialization.cc
index 7ade44c6c18e011b27e18d160cf14e55a2190e0b..de22145e1fb8b3e0aef25cf96bd28fa784f54ab1 100644
--- a/src/compiler/js-native-context-specialization.cc
+++ b/src/compiler/js-native-context-specialization.cc
@@ -1280,7 +1280,7 @@ JSNativeContextSpecialization::BuildElementAccess(
       element_type = Type::Number();
       element_machine_type = MachineType::Float64();
     } else if (IsFastSmiElementsKind(elements_kind)) {
-      element_type = type_cache_.kSmi;
+      element_type = Type::SignedSmall();
       element_machine_type = MachineType::TaggedSigned();
     }
     ElementAccess element_access = {kTaggedBase, FixedArray::kHeaderSize,