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

src/runtime/runtime.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_RUNTIME_RUNTIME_H_
 #define V8_RUNTIME_RUNTIME_H_
 
 #include "src/allocation.h"
 #include "src/base/platform/time.h"
 #include "src/objects.h"
@@ skipping 811 matching lines @@
   F(SubString, 3, 1)                      \
   F(StringAdd, 2, 1)                      \
   F(InternalizeString, 1, 1)              \
   F(StringMatch, 3, 1)                    \
   F(StringCharCodeAtRT, 2, 1)             \
   F(StringCompare, 2, 1)                  \
   F(StringBuilderConcat, 3, 1)            \
   F(StringBuilderJoin, 3, 1)              \
   F(SparseJoinWithSeparator, 3, 1)        \
   F(StringToArray, 2, 1)                  \
-  F(StringToLowerCase, 1, 1)              \
-  F(StringToUpperCase, 1, 1)              \
   F(StringLessThan, 2, 1)                 \
   F(StringLessThanOrEqual, 2, 1)          \
   F(StringGreaterThan, 2, 1)              \
   F(StringGreaterThanOrEqual, 2, 1)       \
   F(StringEqual, 2, 1)                    \
   F(StringNotEqual, 2, 1)                 \
   F(FlattenString, 1, 1)                  \
   F(StringCharFromCode, 1, 1)             \
   F(ExternalStringGetChar, 2, 1)          \
   F(StringCharCodeAt, 2, 1)
@@ skipping 308 matching lines @@
 
 class DeclareGlobalsEvalFlag : public BitField<bool, 0, 1> {};
 class DeclareGlobalsNativeFlag : public BitField<bool, 1, 1> {};
 STATIC_ASSERT(LANGUAGE_END == 3);
 class DeclareGlobalsLanguageMode : public BitField<LanguageMode, 2, 2> {};
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_RUNTIME_H_