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

test/mjsunit/function.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 62 matching lines @@
 
 var x = {}; x.toString = function() { return 'x'; };
 var y = {}; y.toString = function() { return 'y'; };
 var z = {}; z.toString = function() { return 'return x*y'; }
 var f = Function(x, y, z);
 assertEquals(25, f(5, 5));
 assertEquals(42, f(2, 21));
 f = new Function(x, y, z);
 assertEquals(25, f(5, 5));
 assertEquals(42, f(2, 21));
-