Partially revert r21254 due to WebKit test failure.

TBR=danno@chromium.org
BUG=

Review URL: https://codereview.chromium.org/280523002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21257 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/regexp.js

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-"use strict";
-
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Object = global.Object;