[bootstrapper] Remove Intl experimental natives files

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 481 matching lines @@
   sources = [
     "src/js/macros.py",
     "src/messages.h",
     "src/js/harmony-atomics.js",
   ]
 
   outputs = [
     "$target_gen_dir/experimental-libraries.cc",
   ]
 
-  if (v8_enable_i18n_support) {
-    sources += [
-      "src/js/datetime-format-to-parts.js",
-      "src/js/icu-case-mapping.js",
-    ]
-  }
-
   args = [
            rebase_path("$target_gen_dir/experimental-libraries.cc",
                        root_build_dir),
            "EXPERIMENTAL",
          ] + rebase_path(sources, root_build_dir)
 
   if (v8_use_external_startup_data) {
     outputs += [ "$target_gen_dir/libraries_experimental.bin" ]
     args += [
       "--startup_blob",
@@ skipping 2582 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_data_section_fuzzer") {
 }