Fix for 9805, <hr> not positioned properly following a previous empty sibling

    Fix for 9805, <hr> not positioned properly following a previous empty sibling
        that had clear:both set on it.  Update self-collapsing block clearance
        behavior to match what is specified in the latest draft of CSS2.1.

        Reviewed by Eric

        Added fast/block/margin-collapse/empty-clear-blocks.html

        * rendering/RenderBlock.cpp:
        (WebCore::RenderBlock::clearFloatsIfNeeded):
        (WebCore::RenderBlock::handleBottomOfBlock):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@16442 268f45cc-cd09-0410-ab3c-d52691b4dbfc