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

test/mjsunit/harmony/array-find.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 259 matching lines @@
 assertThrows('Array.prototype.find.call({}, /\d+/)', TypeError);
 
 assertThrows('Array.prototype.find.apply({}, null, [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, undefined, [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, 0, [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, true, [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, false, [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, "", [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, {}, [])', TypeError);
 assertThrows('Array.prototype.find.apply({}, [], [])', TypeError);
-assertThrows('Array.prototype.find.apply({}, /\d+/, [])', TypeError);
+assertThrows('Array.prototype.find.apply({}, /\d+/, [])', TypeError);