Added check for trailing whitespaces and corrected existing violations.

test/mjsunit/object-prevent-extensions.js

Index: test/mjsunit/object-prevent-extensions.js
diff --git a/test/mjsunit/object-prevent-extensions.js b/test/mjsunit/object-prevent-extensions.js
index dc32342c0e6f7c58fb5594148a309de4e06957a1..322a2cb5431655943a0c5a8878a8b293fc4cf4bd 100644
--- a/test/mjsunit/object-prevent-extensions.js
+++ b/test/mjsunit/object-prevent-extensions.js
@@ -33,7 +33,7 @@ var obj1 = {};
 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);