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

test/mjsunit/nans.js

 // 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 79 matching lines @@
     var floats = new Float32Array(bytes.buffer);
     assertTrue(isNaN(floats[0]));
     assertTrue(isNaN(floats[0]*2.0));
     assertTrue(isNaN(floats[0] + 0.5));
   }
 
   TestAllModes(f);
 }
 
 TestFloatQuietNan();
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