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

test/mjsunit/stack-traces-2.js

 // Copyright 2011 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 66 matching lines @@
 testTraceNativeConstructor(RegExp);  // Does ToString on argument.
 testTraceNativeConstructor(Date);    // Does ToNumber on argument.
 
 // QuickSort has builtins object as receiver, and is non-native
 // builtin. Should not be omitted with the --builtins-in-stack-traces flag.
 testNotOmittedBuiltin(function(){ [thrower, 2].sort(function (a,b) {
                                                      (b < a) - (a < b); });
                       }, "QuickSort");
 
 // Not omitted even though ADD from runtime.js is a non-native builtin.
-testNotOmittedBuiltin(function(){ thrower + 2; }, "ADD");
+testNotOmittedBuiltin(function(){ thrower + 2; }, "ADD");