[serializer] checksum a larger part of the code snapshot.

src/snapshot/deserializer.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/snapshot/deserializer.h"
 
 #include "src/bootstrapper.h"
 #include "src/external-reference-table.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
@@ skipping 145 matching lines @@
       isolate->heap()->RegisterReservationsForBlackAllocation(reservations_);
     }
     CommitPostProcessedObjects(isolate);
     return scope.CloseAndEscape(result);
   }
 }
 
 Deserializer::~Deserializer() {
   // TODO(svenpanne) Re-enable this assertion when v8 initialization is fixed.
   // DCHECK(source_.AtEOF());
+#ifdef DEBUG
   for (int space = 0; space < kNumberOfPreallocatedSpaces; space++) {
     int chunk_index = current_chunk_[space];
     CHECK_EQ(reservations_[space].length(), chunk_index + 1);
     CHECK_EQ(reservations_[space][chunk_index].end, high_water_[space]);
   }
   CHECK_EQ(allocated_maps_.length(), next_map_index_);
+#endif  // DEBUG
 }
 
 // This is called on the roots.  It is the driver of the deserialization
 // process.  It is also called on the body of each function.
 void Deserializer::VisitPointers(Object** start, Object** end) {
   // The space must be new space.  Any other space would cause ReadChunk to try
   // to update the remembered using NULL as the address.
   ReadData(start, end, NEW_SPACE, NULL);
 }
 
@@ skipping 640 matching lines @@
 
       default:
         CHECK(false);
     }
   }
   CHECK_EQ(limit, current);
   return true;
 }
 }  // namespace internal
 }  // namespace v8