Addresses issue in IE11 where the default port number of `:80` is unexpectedly included on `link.host` for links dynamically created by scripts. Props westonruter, afercia for testing. See #38409. Fixes #40198. Built from https://develop.svn.wordpress.org/trunk@40318 git-svn-id: http://core.svn.wordpress.org/trunk@40225 1a063a9b-81f0-0310-95a4-ce76da25c4cd