Revert of [builtins] Also migrate String.prototype.toLowerCase/toUpperCase to C++.

src/contexts.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_CONTEXTS_H_
 #define V8_CONTEXTS_H_
 
 #include "src/heap/heap.h"
 #include "src/objects.h"
 
@@ skipping 66 matching lines @@
   V(OBJECT_FREEZE, JSFunction, object_freeze)                           \
   V(OBJECT_GET_PROTOTYPE_OF, JSFunction, object_get_prototype_of)       \
   V(OBJECT_IS_EXTENSIBLE, JSFunction, object_is_extensible)             \
   V(OBJECT_IS_FROZEN, JSFunction, object_is_frozen)                     \
   V(OBJECT_IS_SEALED, JSFunction, object_is_sealed)                     \
   V(OBJECT_KEYS, JSFunction, object_keys)                               \
   V(REFLECT_APPLY_INDEX, JSFunction, reflect_apply)                     \
   V(REFLECT_CONSTRUCT_INDEX, JSFunction, reflect_construct)             \
   V(REFLECT_DEFINE_PROPERTY_INDEX, JSFunction, reflect_define_property) \
   V(REFLECT_DELETE_PROPERTY_INDEX, JSFunction, reflect_delete_property) \
-  V(STRING_TO_LOWER_CASE_INDEX, JSFunction, string_to_lower_case)       \
-  V(STRING_TO_UPPER_CASE_INDEX, JSFunction, string_to_upper_case)       \
   V(SPREAD_ARGUMENTS_INDEX, JSFunction, spread_arguments)               \
   V(SPREAD_ITERABLE_INDEX, JSFunction, spread_iterable)                 \
   V(MATH_FLOOR, JSFunction, math_floor)                                 \
   V(MATH_SQRT, JSFunction, math_sqrt)
 
 #define NATIVE_CONTEXT_IMPORTED_FIELDS(V)                                   \
   V(ARRAY_CONCAT_INDEX, JSFunction, array_concat)                           \
   V(ARRAY_POP_INDEX, JSFunction, array_pop)                                 \
   V(ARRAY_PUSH_INDEX, JSFunction, array_push)                               \
   V(ARRAY_SHIFT_INDEX, JSFunction, array_shift)                             \
@@ skipping 470 matching lines @@
 #endif
 
   STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CONTEXTS_H_