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

test/mjsunit/tools/profile.js

 // Copyright 2009 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 327 matching lines @@
   assertEquals(2, flatProfile.length, 'counted vs. flatProfile');
   for (var i = 0; i < flatProfile.length; ++i) {
     var rec = flatProfile[i];
     assertTrue(rec.label in flatWeights, 'uncounted: ' + rec.label);
     var reference = flatWeights[rec.label];
     assertEquals(reference[0], rec.selfWeight, 'self of ' + rec.label);
     assertEquals(reference[1], rec.totalWeight, 'total of ' + rec.label);
   }
 
 })();
-