While it does not happen often, it is possible for files to be corrupted during the update process. I have had it happen to me in the past. Usually when it happens the file is truncated. Even individual lines can be truncated. Not sure how this happens. When corruption happens it usually happens to very large files.
Another way to test out if there is a corrupt JS file is to add
define('SCRIPT_DEBUG', true);
to your wp-config.php file. This will cause WP to load unminified versions of scripts. If it works like this then one of the minified scripts is likely corrupt.
