Migrate some case conversion functions from JS to CPP builtins

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 981 matching lines @@
     "src/builtins/builtins-date.cc",
     "src/builtins/builtins-debug.cc",
     "src/builtins/builtins-error.cc",
     "src/builtins/builtins-function.cc",
     "src/builtins/builtins-generator.cc",
     "src/builtins/builtins-global.cc",
     "src/builtins/builtins-handler.cc",
     "src/builtins/builtins-ic.cc",
     "src/builtins/builtins-internal.cc",
     "src/builtins/builtins-interpreter.cc",
+    "src/builtins/builtins-intl.cc",
     "src/builtins/builtins-json.cc",
     "src/builtins/builtins-math.cc",
     "src/builtins/builtins-number.cc",
     "src/builtins/builtins-object.cc",
     "src/builtins/builtins-object.h",
     "src/builtins/builtins-promise.cc",
     "src/builtins/builtins-promise.h",
     "src/builtins/builtins-proxy.cc",
     "src/builtins/builtins-reflect.cc",
     "src/builtins/builtins-regexp.cc",
@@ skipping 2108 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_compile_fuzzer") {
 }