[Qt] Unreviewed gardening. Update platform specific expected files after r142280.

* platform/qt/fast/block/float/024-expected.txt: Update after r142280.
* platform/qt/fast/block/margin-collapse/empty-clear-blocks-expected.txt: Update after r142280.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142294 268f45cc-cd09-0410-ab3c-d52691b4dbfc