Add missing initializer for FieldAccess' write_barrier_kind field

Omitting the initializer will give zero-initialization which is equivalent
to kNoWriteBarrier.

Review-Url: https://codereview.chromium.org/1942293002
Cr-Commit-Position: refs/heads/master@{#35989}

src/compiler/js-create-lowering.cc

@@ -933,8 +933,9 @@ Node* JSCreateLowering::AllocateFastLiteral(
     Handle<Name> property_name(
         boilerplate_map->instance_descriptors()->GetKey(i), isolate());
     FieldIndex index = FieldIndex::ForDescriptor(*boilerplate_map, i);
-    FieldAccess access = {kTaggedBase, index.offset(), property_name,
-                          Type::Tagged(), MachineType::AnyTagged()};
+    FieldAccess access = {
+        kTaggedBase,    index.offset(),           property_name,
+        Type::Tagged(), MachineType::AnyTagged(), kFullWriteBarrier};
     Node* value;
     if (boilerplate->IsUnboxedDoubleField(index)) {
       access.machine_type = MachineType::Float64();