Revert of [date] Add ICU backend for timezone info behind a flag

test/mjsunit/icu-date-to-string.js

Index: test/mjsunit/icu-date-to-string.js
diff --git a/test/mjsunit/icu-date-to-string.js b/test/mjsunit/icu-date-to-string.js
deleted file mode 100644
index c974ad8049a2b294d5103257ca7f29936ec7db0d..0000000000000000000000000000000000000000
--- a/test/mjsunit/icu-date-to-string.js
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2017 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.
-
-// Flags: --icu-timezone-data
-// Environment Variables: TZ=Europe/Madrid LC_ALL=de
-
-assertEquals(
-   "Sun Dec 31 1989 00:00:00 GMT+0100 (Mitteleuropäische Normalzeit)",
-   new Date(1990, 0, 0).toString());
-
-assertEquals(
-   "Sat Jun 30 1990 00:00:00 GMT+0200 (Mitteleuropäische Sommerzeit)",
-   new Date(1990, 6, 0).toString());