Attrs: Force reflow in select value setter

305eefe6abadbac021a84d031cb4649022657ac7 commit disturbed an ancient, dormant <a href="http://bugs.jquery.com/ticket/2252">evil</a>, that ruined poor <a href="http://swarm.jquery.org/result/1481215">tests</a> for attributes module in IE6,
bug ticket and <a href="http://asyncweb.blogspot.ru/2012/04/jquery-attr-selected-property-ie6-bug.html">internet</a> are filled with sometimes weird sometimes incorrect "fixes" for this issue, but no one awesome as i am, so only i could do it.

I do remember we no longer land IE6 only fixes and `try...catch` is lame (although it could be done in a different way), so alternative for this would be a conditional run of failed assertion.