Flatten property_kind into state. Add UNKNOWN as a state for dict-mode receivers

src/accessors.cc

Index: src/accessors.cc
diff --git a/src/accessors.cc b/src/accessors.cc
index 03ab9c4a3a8aeb9ccc725eccb6282647ee6eec46..a1a89d3aa26d350e66d71dc25a56813340a07dd9 100644
--- a/src/accessors.cc
+++ b/src/accessors.cc
@@ -181,7 +181,7 @@ void Accessors::ArgumentsIteratorSetter(
   if (SetPropertyOnInstanceIfInherited(isolate, info, name, value)) return;
 
   LookupIterator it(object, Utils::OpenHandle(*name));
-  CHECK(it.HasProperty());
+  CHECK_EQ(LookupIterator::ACCESSOR, it.state());
   DCHECK(it.HolderIsReceiverOrHiddenPrototype());
   Object::SetDataProperty(&it, value);
 }