Added check for trailing whitespaces and corrected existing violations.

test/mjsunit/object-prevent-extensions.js

 // Copyright 2010 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.
 
 // Tests the Object.preventExtensions method - ES 15.2.3.10
 
 
 var obj1 = {};
 // Extensible defaults to true.
 assertTrue(Object.isExtensible(obj1));
 Object.preventExtensions(obj1);
 
-// Make sure the is_extensible flag is set. 
+// Make sure the is_extensible flag is set.
 assertFalse(Object.isExtensible(obj1));
 obj1.x = 42;
 assertEquals(undefined, obj1.x);
 
 // Try adding a new element.
 obj1[1] = 42;
 assertEquals(undefined, obj1[1]);
 
 
 // Try when the object has an existing property.
@@ skipping 60 matching lines @@
 
 // Test that attributes on functions are also handled correctly.
 function foo() {
   return 42;
 }
 
 Object.preventExtensions(foo);
 
 foo.x = 29;
 assertEquals(undefined, foo.x);