[bootstrapper] Remove Intl experimental natives files

src/js/icu-case-mapping.js

Index: src/js/icu-case-mapping.js
diff --git a/src/js/icu-case-mapping.js b/src/js/icu-case-mapping.js
deleted file mode 100644
index 9806249d7105d84b3563ff24e7259c83832fcff4..0000000000000000000000000000000000000000
--- a/src/js/icu-case-mapping.js
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2016 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.
-
-(function(global, utils) {
-"use strict";
-
-%CheckIsBootstrapping();
-
-var GlobalString = global.String;
-var OverrideFunction = utils.OverrideFunction;
-var ToLowerCaseI18N = utils.ImportNow("ToLowerCaseI18N");
-var ToUpperCaseI18N = utils.ImportNow("ToUpperCaseI18N");
-var ToLocaleLowerCaseI18N = utils.ImportNow("ToLocaleLowerCaseI18N");
-var ToLocaleUpperCaseI18N = utils.ImportNow("ToLocaleUpperCaseI18N");
-
-OverrideFunction(GlobalString.prototype, 'toLowerCase', ToLowerCaseI18N, true);
-OverrideFunction(GlobalString.prototype, 'toUpperCase', ToUpperCaseI18N, true);
-OverrideFunction(GlobalString.prototype, 'toLocaleLowerCase',
-                 ToLocaleLowerCaseI18N, true);
-OverrideFunction(GlobalString.prototype, 'toLocaleUpperCase',
-                 ToLocaleUpperCaseI18N, true);
-
-})