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

test/mjsunit/mirror-boolean.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 38 matching lines @@
 
   // Parse JSON representation and check.
   var fromJSON = eval('(' + json + ')');
   assertEquals('boolean', fromJSON.type, json);
   assertEquals(b, fromJSON.value, json);
 }
 
 
 // Test all boolean values.
 testBooleanMirror(true);
-testBooleanMirror(false);
+testBooleanMirror(false);