[turbofan] Introduce a dedicated ConvertTaggedHoleToUndefined operator.

src/heap/heap.h

 // Copyright 2012 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.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 148 matching lines @@
   V(TypeFeedbackVector, dummy_vector, DummyVector)                             \
   V(PropertyCell, empty_property_cell, EmptyPropertyCell)                      \
   V(WeakCell, empty_weak_cell, EmptyWeakCell)                                  \
   /* Protectors */                                                             \
   V(PropertyCell, array_protector, ArrayProtector)                             \
   V(Cell, is_concat_spreadable_protector, IsConcatSpreadableProtector)         \
   V(PropertyCell, has_instance_protector, HasInstanceProtector)                \
   V(Cell, species_protector, SpeciesProtector)                                 \
   /* Special numbers */                                                        \
   V(HeapNumber, nan_value, NanValue)                                           \
+  V(HeapNumber, hole_nan_value, HoleNanValue)                                  \
   V(HeapNumber, infinity_value, InfinityValue)                                 \
   V(HeapNumber, minus_zero_value, MinusZeroValue)                              \
   V(HeapNumber, minus_infinity_value, MinusInfinityValue)                      \
   /* Caches */                                                                 \
   V(FixedArray, number_string_cache, NumberStringCache)                        \
   V(FixedArray, single_character_string_cache, SingleCharacterStringCache)     \
   V(FixedArray, string_split_cache, StringSplitCache)                          \
   V(FixedArray, regexp_multiple_cache, RegExpMultipleCache)                    \
   V(Object, instanceof_cache_function, InstanceofCacheFunction)                \
   V(Object, instanceof_cache_map, InstanceofCacheMap)                          \
@@ skipping 2529 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_