VM: Make precompiler process constants/fields only once, avoid using pool.InfoAt()

runtime/vm/assembler.cc

 // Copyright (c) 2012, 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/assembler.h"
 
 #include "platform/utils.h"
 #include "vm/cpu.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
@@ skipping 301 matching lines @@
       patchable);
 }
 
 
 RawObjectPool* ObjectPoolWrapper::MakeObjectPool() {
   intptr_t len = object_pool_.length();
   if (len == 0) {
     return Object::empty_object_pool().raw();
   }
   const ObjectPool& result = ObjectPool::Handle(ObjectPool::New(len));
-  const TypedData& info_array = TypedData::Handle(result.info_array());
+  ObjectPoolInfo pool_info(result);
   for (intptr_t i = 0; i < len; ++i) {
     ObjectPool::EntryType info = object_pool_[i].type_;
-    info_array.SetInt8(i, static_cast<int8_t>(info));
+    pool_info.SetInfoAt(i, info);
     if (info == ObjectPool::kTaggedObject) {
       result.SetObjectAt(i, *object_pool_[i].obj_);
     } else {
       result.SetRawValueAt(i, object_pool_[i].raw_value_);
     }
   }
   return result.raw();
 }
 
 
 }  // namespace dart