Reviewed by Darin Adler.

        Rebaseline fast/multicol pixel results on mac
        https://bugs.webkit.org/show_bug.cgi?id=39241

        * fast/multicol/client-rects-expected.checksum:
        * fast/multicol/client-rects-expected.png:
        * platform/mac/fast/multicol/float-multicol-expected.png:
        * platform/mac/fast/multicol/layers-in-multicol-expected.checksum: Added.
        * platform/mac/fast/multicol/layers-in-multicol-expected.png: Added.
        * platform/mac/fast/multicol/nested-columns-expected.checksum: Added.
        * platform/mac/fast/multicol/nested-columns-expected.png: Added.
        * platform/mac/fast/multicol/positioned-with-constrained-height-expected.checksum:
        * platform/mac/fast/multicol/positioned-with-constrained-height-expected.png:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@59628 268f45cc-cd09-0410-ab3c-d52691b4dbfc