Remove IE8-specific shorthand style property logic

[aweary]

This logic was only here for IE8. Setting .stype[prop] for shorthand properties works fine in all other tested browsers.

Testing strategy

Used the following snippet to verify shorthand property behavior

 <span id="span" style="background-color: blue; font-size: 20px; font-family: monospace; border-width: 5px; border-style: solid; border-color: red; outline-width: 10px; outline-color: green;">Click Me</span>
  <script>
    var span = document.getElementById('span');
    span.onclick = function() {
      span.style.font = '';
      span.style.background = '';
      span.style.outline = '';
      span.style.border = '';
    }
  </script>

Tested Browsers

Verified all listed browsers behaved as expected (unset the shorthand style property)

• IE9
• Firefox 3 (OS X Snow Leopard)
• Safari (iOS 6)
• Safari 4 (OS X Snow Leopard)
• Android Browser (Android 4.1, S3)
• Chrome (Android 4.4, Note 4)
• Windows Phone 8.1
• Opera 12.12

edit I updated the test to be more robust and noticed that font does not work in Android Browser for Android 4.1 or iOS 4. We may still need this if we support those browsers, though we should be able to remove a number of the properties.

[aweary]

Older versions of iOS and Android are giving me trouble here, so I'm closing this. Will likely open another PR with a reduced implementation of this.