r189916 unskipped four multicolumn tests. However, two of these tests are still failing on the GTK port: imported/w3c/css/css-multicol-1/multicol-rule-inset-000.xht [ ImageOnlyFailure ] imported/w3c/css/css-multicol-1/multicol-rule-outset-000.xht [ ImageOnlyFailure ] These tests are still broken even after renaming them to .xhtml (bug #152455).
These tests were fixed by r194845.