[runtime] We don't need an actual instance type for JSIteratorResult.

src/types.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <iomanip>
 
 #include "src/types.h"
 
 #include "src/handles-inl.h"
 #include "src/ostreams.h"
@@ skipping 197 matching lines @@
     case JS_GLOBAL_OBJECT_TYPE:
     case JS_GLOBAL_PROXY_TYPE:
     case JS_ARRAY_BUFFER_TYPE:
     case JS_ARRAY_TYPE:
     case JS_TYPED_ARRAY_TYPE:
     case JS_DATA_VIEW_TYPE:
     case JS_SET_TYPE:
     case JS_MAP_TYPE:
     case JS_SET_ITERATOR_TYPE:
     case JS_MAP_ITERATOR_TYPE:
-    case JS_ITERATOR_RESULT_TYPE:
     case JS_WEAK_MAP_TYPE:
     case JS_WEAK_SET_TYPE:
     case JS_PROMISE_TYPE:
     case JS_BOUND_FUNCTION_TYPE:
       if (map->is_undetectable()) return kUndetectable;
       return kOtherObject;
     case JS_FUNCTION_TYPE:
       if (map->is_undetectable()) return kUndetectable;
       return kFunction;
     case JS_REGEXP_TYPE:
@@ skipping 1133 matching lines @@
 #undef CONSTRUCT_SIMD_TYPE
 
 // -----------------------------------------------------------------------------
 // Instantiations.
 
 template class Type::Iterator<i::Map>;
 template class Type::Iterator<i::Object>;
 
 }  // namespace internal
 }  // namespace v8