Setting Symbol.length to 0 according to the spec

BUG=v8:4882
LOG=n

Review URL: https://codereview.chromium.org/1863543002

Cr-Commit-Position: refs/heads/master@{#35255}

src/bootstrapper.cc

@@ -1259,7 +1259,7 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
                         prototype, Builtins::kSymbolConstructor);
     symbol_fun->shared()->set_construct_stub(
         *isolate->builtins()->SymbolConstructor_ConstructStub());
-    symbol_fun->shared()->set_length(1);
+    symbol_fun->shared()->set_length(0);
     symbol_fun->shared()->DontAdaptArguments();
     native_context()->set_symbol_function(*symbol_fun);
 

test/mjsunit/es6/symbols.js

@@ -86,6 +86,7 @@ TestPrototype()
 
 
 function TestConstructor() {
+  assertEquals(0, Symbol.length);
   assertSame(Function.prototype, Symbol.__proto__)
   assertFalse(Object === Symbol.prototype.constructor)
   assertFalse(Symbol === Object.prototype.constructor)