Enable on stack reload in standalone embedder

runtime/vm/isolate_reload.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/isolate_reload.h"
 
 #include "vm/become.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
@@ skipping 239 matching lines @@
 
   // Ensure all functions on the stack have unoptimized code.
   EnsuredUnoptimizedCodeForStack();
   // Deoptimize all code that had optimizing decisions that are dependent on
   // assumptions from field guards or CHA or deferred library prefixes.
   // TODO(johnmccutchan): Deoptimizing dependent code here (before the reload)
   // is paranoid. This likely can be moved to the commit phase.
   DeoptimizeDependentCode();
   Checkpoint();
 
-  // Block class finalization attempts when calling into the library
-  // tag handler.
-  I->BlockClassFinalization();
   Object& result = Object::Handle(thread->zone());
   {
     TransitionVMToNative transition(thread);
     Api::Scope api_scope(thread);
 
     Dart_Handle retval =
         (I->library_tag_handler())(Dart_kScriptTag,
-                                Api::NewHandle(thread, Library::null()),
-                                Api::NewHandle(thread, root_lib_url.raw()));
+                                   Api::NewHandle(thread, Library::null()),
+                                   Api::NewHandle(thread, root_lib_url.raw()));
     result = Api::UnwrapHandle(retval);
   }
-  I->UnblockClassFinalization();
   if (result.IsError()) {
     ReportError(Error::Cast(result));
   }
 }
 
 
 void IsolateReloadContext::RegisterClass(const Class& new_cls) {
   const Class& old_cls = Class::Handle(OldClassOrNull(new_cls));
   if (old_cls.IsNull()) {
     Isolate::Current()->class_table()->Register(new_cls);
@@ skipping 901 matching lines @@
         ASSERT(!super_cls.IsNull());
         super_cls.AddDirectSubclass(cls);
       }
     }
   }
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart