Remove all harmony runtime flags which shipped in M51

test/mjsunit/es6/function-name.js

 // Copyright 2015 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: --harmony-function-name
 
 (function testVariableDeclarationsFunction() {
   'use strict';
   var a = function(){};
   assertEquals('a', a.name);
   let b = () => {};
   assertEquals('b', b.name);
   const c = ((function(){}));
   assertEquals('c', c.name);
 
@@ skipping 347 matching lines @@
   var g = function*() {};
   var obj = {
     ['h']: function() {},
     i: () => {}
   };
   assertEquals('function () {}', f.toString());
   assertEquals('function* () {}', g.toString());
   assertEquals('function () {}', obj.h.toString());
   assertEquals('() => {}', obj.i.toString());
 })();