The test for https://trac.webkit.org/changeset/215874/webkit (css3/viewport-percentage-lengths/vh-auto-size.html) does not clean up state in DumpRenderTree and causes subsequent tests to fail. The test was skipped on wk1 in https://trac.webkit.org/changeset/215882/webkit. From the diffs in this run, we see that the view is 1000x1038 instead of 800x600 for the failing tests: https://build.webkit.org/results/Apple%20Sierra%20Release%20WK1%20(Tests)/r215879%20(1067)/results.html