Don't leak the global object in the Function constructor.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 831f76dd778d77e88af030d9cebd32710bc93c26..703e20fc189748cc1823eda7f4d5632299ddc5cb 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -8248,7 +8248,7 @@ static Object* Runtime_NewObjectHelper(Isolate* isolate,
       // instead of a new JSFunction object. This way, errors are
       // reported the same way whether or not 'Function' is called
       // using 'new'.
-      return isolate->context()->global_object();
+      return isolate->context()->global_proxy();
     }
   }