r198843 added several layout tests for RTL scrollbars. It marked them all as expected to fail because "RTL Scrollbars are only implemented on certain versions of OS X," however fast/scrolling/rtl-scrollbars-listbox-scroll.html usually passes on the GTK port. It has been flaky, however.
Updated expectations in r199270.
The test(s) filed under this bug have been consistently passing for the last 4000 revisions. Marking bug as fixed.
Committed r263254: <https://trac.webkit.org/changeset/263254>