Parse location.href with an anchor for IE

This is a follow up to https://github.com/madrobby/zepto/pull/1046. It turns out that IE always adds the port to `window.location.host`, but not to `a.host`. This doesn't show up in tests because they are run on port 3000, so the port is always present in `a.host` too.
I can open another PR for a comment if you'd like :smile: