Avoid allocating a whole new page for two one-element arrays when finalizing the VM isolate.

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 5284 matching lines @@
 
 #if defined(DEBUG)
     int32_t section_marker = Read<int32_t>();
     ASSERT(section_marker == kSectionMarker);
 #endif
 
     refs = refs_;
     refs_ = NULL;
   }
 
+  // Move remaining bump allocation space to the freelist so it used by C++
+  // allocations (e.g., FinalizeVMIsolate) before allocating new pages.
+  heap_->old_space()->AbandonBumpAllocation();
+
   Symbols::InitOnceFromSnapshot(isolate());
 
   Object::set_vm_isolate_snapshot_object_table(refs);
 
 #if defined(DEBUG)
   isolate()->ValidateClassTable();
 #endif
 }
 
 void Deserializer::ReadIsolateSnapshot(ObjectStore* object_store) {
@@ skipping 320 matching lines @@
     thread_->isolate()->SetupImagePage(data_buffer_,
                                        /* is_executable */ false);
   }
 
   deserializer.ReadIsolateSnapshot(thread_->isolate()->object_store());
 
   return ApiError::null();
 }
 
 }  // namespace dart