Remove all harmony runtime flags which shipped in M51

test/mjsunit/harmony/regexp-no-change-exec.js

Index: test/mjsunit/harmony/regexp-no-change-exec.js
diff --git a/test/mjsunit/harmony/regexp-no-change-exec.js b/test/mjsunit/harmony/regexp-no-change-exec.js
deleted file mode 100644
index 30b5050945051ef61178019eec66dd1891e305ef..0000000000000000000000000000000000000000
--- a/test/mjsunit/harmony/regexp-no-change-exec.js
+++ /dev/null
@@ -1,9 +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.
-
-// Flags: --no-harmony-regexp-exec
-
-class MyError extends Error { }
-RegExp.prototype.exec = () => { throw new MyError() };
-assertEquals(null, "foo".match(/bar/));