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

test/mjsunit/debug-function-scopes.js

 // Copyright 2012 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 141 matching lines @@
   var mirror = Debug.MakeMirror(f);
   assertEquals(0, mirror.scopeCount());
 }
 
 CheckNoScopeVisible(Number);
 
 CheckNoScopeVisible(Function.toString);
 
 // This getter is known to be implemented as closure.
 CheckNoScopeVisible(new Error().__lookupGetter__("stack"));
-