Fix off-by-one issue in clustered snapshot implementation and api impl

runtime/vm/clustered_snapshot.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/clustered_snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
@@ skipping 4294 matching lines @@
   delete[] clusters_by_cid_;
 }
 
 
 SerializationCluster* Serializer::NewClusterForClass(intptr_t cid) {
 #if defined(DART_PRECOMPILED_RUNTIME)
   UNREACHABLE();
   return NULL;
 #else
   Zone* Z = zone_;
-  if ((cid > kNumPredefinedCids) ||
+  if ((cid >= kNumPredefinedCids) ||
       (cid == kInstanceCid) ||
       RawObject::IsTypedDataViewClassId(cid)) {
     Push(isolate()->class_table()->At(cid));
     return new (Z) InstanceSerializationCluster(cid);
   }
   if (RawObject::IsExternalTypedDataClassId(cid)) {
     return new (Z) ExternalTypedDataSerializationCluster(cid);
   }
   if (RawObject::IsTypedDataClassId(cid)) {
     return new (Z) TypedDataSerializationCluster(cid);
@@ skipping 303 matching lines @@
 
 Deserializer::~Deserializer() {
   delete[] clusters_;
 }
 
 
 DeserializationCluster* Deserializer::ReadCluster() {
   intptr_t cid = ReadCid();
 
   Zone* Z = zone_;
-  if ((cid > kNumPredefinedCids) ||
+  if ((cid >= kNumPredefinedCids) ||
       (cid == kInstanceCid) ||
       RawObject::IsTypedDataViewClassId(cid)) {
     return new (Z) InstanceDeserializationCluster(cid);
   }
   if (RawObject::IsExternalTypedDataClassId(cid)) {
     return new (Z) ExternalTypedDataDeserializationCluster(cid);
   }
   if (RawObject::IsTypedDataClassId(cid)) {
     return new (Z) TypedDataDeserializationCluster(cid);
   }
@@ skipping 559 matching lines @@
 
   deserializer.ReadVMSnapshot();
 
   Dart::set_instructions_snapshot_buffer(instructions_buffer_);
   Dart::set_data_snapshot_buffer(data_buffer_);
 
   return ApiError::null();
 }
 
 }  // namespace dart