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

test/mjsunit/debug-breakpoints.js

 // Copyright 2008 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 204 matching lines @@
   [16, "f2(1,2),[B0]f3()"],
   [22, "+[B0]f3()"]
 ];
 for(var i = 0; i < scenario.length; i++) {
   bp1 = setBreakpointByPosition(h, scenario[i][0],
       Debug.BreakPositionAlignment.BreakPosition);
   assertTrue(Debug.showBreakPoints(h, undefined,
       Debug.BreakPositionAlignment.BreakPosition).indexOf(scenario[i][1]) > 0);
   Debug.clearBreakPoint(bp1);
 }
-