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

test/mjsunit/regress/regress-crbug-245480.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 69 matching lines @@
 %OptimizeFunctionOnNextCall(f);
 var a = f(10);
 
 function g(a) {
   return a[0];
 }
 
 var b = [0];
 g(b);
 g(b);
-assertEquals(undefined, g(a));
+assertEquals(undefined, g(a));