[es6] don't "replace" Object.prototype.toString for --harmony-tostring

src/harmony-tostring.js

Index: src/harmony-tostring.js
diff --git a/src/harmony-tostring.js b/src/harmony-tostring.js
index 4f4f986fd26bc904f45c92c2b202732d0a4cf709..0c3f3ca9e21ec8b168c53a6d2922fa8cc45be8fb 100644
--- a/src/harmony-tostring.js
+++ b/src/harmony-tostring.js
@@ -32,23 +32,3 @@ function HarmonyToStringExtendSymbolPrototype() {
 }
 
 HarmonyToStringExtendSymbolPrototype();
-
-function HarmonyToStringExtendObjectPrototype() {
-  %CheckIsBootstrapping();
-
-  // Can't use InstallFunctions() because will fail in Debug mode.
-  // Emulate InstallFunctions() here.
-  %FunctionSetName(ObjectToStringHarmony, "toString");
-  %FunctionRemovePrototype(ObjectToStringHarmony);
-  %SetNativeFlag(ObjectToStringHarmony);
-
-  // Set up the non-enumerable functions on the Array prototype object.
-  var desc = ToPropertyDescriptor({
-    value: ObjectToStringHarmony
-  });
-  DefineOwnProperty($Object.prototype, "toString", desc, false);
-
-  %ToFastProperties($Object.prototype);
-}
-
-HarmonyToStringExtendObjectPrototype();