Simplify v8/Isolate teardown.

src/isolate.cc

 // Copyright 2012 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 1533 matching lines @@
 
   { LockGuard<Mutex> lock_guard(&process_wide_mutex_);
     thread_data_table_->RemoveAllThreads(this);
   }
 
   if (serialize_partial_snapshot_cache_ != NULL) {
     delete[] serialize_partial_snapshot_cache_;
     serialize_partial_snapshot_cache_ = NULL;
   }
 
-  if (!IsDefaultIsolate()) {
-    delete this;
-  }
+  delete this;
 
   // Restore the previous current isolate.
   SetIsolateThreadLocals(saved_isolate, saved_data);
 }
 
 
 void Isolate::GlobalTearDown() {
   delete thread_data_table_;
 }
 
@@ skipping 683 matching lines @@
       Handle<JSObject> obj = factory()->NewJSObjectFromMap(map);
       JSObject::NormalizeProperties(obj, KEEP_INOBJECT_PROPERTIES, 8);
       JSObject::SetProperty(registry, name, obj, NONE, STRICT).Assert();
     }
   }
   return Handle<JSObject>::cast(factory()->symbol_registry());
 }
 
 
 } }  // namespace v8::internal