[es6] Support Function name inference in variable declarations

test/mjsunit/harmony/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);
+
+  var x = function(){}, y = () => {}, z = function withName() {};
+  assertEquals('x', x.name);
+  assertEquals('y', y.name);
+  assertEquals('withName', z.name);
+})();
+
+(function testVariableDeclarationsClass() {
+  'use strict';
+  var a = class {};
+  assertEquals('a', a.name);
+  let b = ((class {}));
+  assertEquals('b', b.name);
+  // Should not overwrite name property.
+  const c = class { static name() { } }
+  assertEquals('function', typeof c.name);
+
+  var x = class {}, y = class NamedClass {};
+  assertEquals('x', x.name);
+  assertEquals('NamedClass', y.name);
+})();