Remove all harmony runtime flags which shipped in M51

test/mjsunit/es6/string-replace.js

Index: test/mjsunit/es6/string-replace.js
diff --git a/test/mjsunit/harmony/string-replace.js b/test/mjsunit/es6/string-replace.js
similarity index 94%
rename from test/mjsunit/harmony/string-replace.js
rename to test/mjsunit/es6/string-replace.js
index 208c483fd07628a309a7098db682710611be81ea..0beb57a5368607af0ead51fb3f1d334c2c41b664 100644
--- a/test/mjsunit/harmony/string-replace.js
+++ b/test/mjsunit/es6/string-replace.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.
 
-// Flags: --harmony-regexp-subclass
-
 var pattern = {
   [Symbol.replace]: (string, newValue) => string + newValue
 };