Setting Symbol.length to 0 according to the spec

test/mjsunit/es6/symbols.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 68 matching lines @@
   assertSame(Symbol.prototype, Symbol().__proto__)
   assertSame(Symbol.prototype, Object(Symbol()).__proto__)
   for (var i in symbols) {
     assertSame(Symbol.prototype, symbols[i].__proto__)
   }
 }
 TestPrototype()
 
 
 function TestConstructor() {
+  assertEquals(0, Symbol.length);
   assertSame(Function.prototype, Symbol.__proto__)
   assertFalse(Object === Symbol.prototype.constructor)
   assertFalse(Symbol === Object.prototype.constructor)
   assertSame(Symbol, Symbol.prototype.constructor)
   assertSame(Symbol, Symbol().__proto__.constructor)
   assertSame(Symbol, Object(Symbol()).__proto__.constructor)
   for (var i in symbols) {
     assertSame(Symbol, symbols[i].__proto__.constructor)
   }
 }
@@ skipping 457 matching lines @@
   assertEquals(expected, JSON.stringify(input));
   assertEquals(expected, JSON.stringify(input, null, 0));
 }
 
 TestStringify(undefined, Symbol("a"));
 TestStringify('[{}]', [Object(Symbol())]);
 var symbol_wrapper = Object(Symbol("a"))
 TestStringify('{}', symbol_wrapper);
 symbol_wrapper.a = 1;
 TestStringify('{"a":1}', symbol_wrapper);