Make sure files end with exactly one new line and police this in presubmit.

src/allocation-tracker.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 117 matching lines @@
   SnapshotObjectId allocation_trace_buffer_[kMaxAllocationTraceLength];
   HashMap id_to_function_info_;
   List<UnresolvedLocation*> unresolved_locations_;
 
   DISALLOW_COPY_AND_ASSIGN(AllocationTracker);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ALLOCATION_TRACKER_H_
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