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

test/mjsunit/regress/regress-1112.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 15 matching lines @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Regression test making sure that defineProperty on the global proxy
 // defines the property on the global object.
 
 Object.defineProperty(this,
                       1,
                       { configurable: true, enumerable: true, value: 3 });
 assertEquals(3, this[1]);
 assertTrue(this.hasOwnProperty("1"));
-