fixes #5513 add toStringTag for global object

Author: duongnhn

lib/Runtime/Library/JavascriptLibrary.cpp

@@ -1141,6 +1141,8 @@ namespace Js
         AddMember(globalObject, PropertyIds::NaN, nan, PropertyNone);
         AddMember(globalObject, PropertyIds::Infinity, positiveInfinite, PropertyNone);
         AddMember(globalObject, PropertyIds::undefined, undefinedValue, PropertyNone);
+        // Note: for global object, we need to set toStringTag to global like other engines (v8)
+        AddMember(globalObject, PropertyIds::_symbolToStringTag, scriptContext->GetPropertyString(PropertyIds::global) , PropertyNone);
 
         // Note: Any global function added/removed/changed here should also be updated in JavascriptLibrary::ProfilerRegisterBuiltinFunctions
         // so that the new functions show up in the profiler too.

test/Object/rlexe.xml

@@ -486,4 +486,10 @@
       <compile-flags>-args summary -endargs -ES2018ObjectRestSpread -off:simplejit</compile-flags>
     </default>
   </test>
+  <test>
+    <default>
+      <files>toStringWithGlobalObject.js</files>
+      <baseline>toStringWithGlobalObject.baseline</baseline>
+    </default>
+  </test>
 </regress-exe>

test/Object/toStringWithGlobalObject.baseline

@@ -0,0 +1,2 @@
+[object global]
+global

test/Object/toStringWithGlobalObject.js

@@ -0,0 +1,8 @@
+//-------------------------------------------------------------------------------------------------------
+// Copyright (C) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
+//-------------------------------------------------------------------------------------------------------
+
+let global = new Function('return this;')();
+console.log(global.toString());
+console.log(global[Symbol.toStringTag]);