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

test/webkit/sort-with-side-effecting-comparisons.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 // 1.  Redistributions of source code must retain the above copyright
 //     notice, this list of conditions and the following disclaimer.
 // 2.  Redistributions in binary form must reproduce the above copyright
 //     notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 array.sort(function(a, b) {
     array.shift();
     if (a < b)
         return -1;
     if (a > b)
         return 1;
     return 0;
 });
 
 testPassed("It worked.");
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