fast/scrolling/mac/scrollbars/overflow-overlay-scrollbar-hovered.html Test is a flaky timeout according to history on macOS Mojave wk2 Debug. The first occurrence of a timeout is at r261168 but there is no indication of a change at that revision caused the timeout. History: https://results.webkit.org/?suite=layout-tests&test=fast%2Fscrolling%2Fmac%2Fscrollbars%2Foverflow-overlay-scrollbar-hovered.html&limit=50000&platform=mac&style=debug&flavor=wk2&version_name=Mojave Diff: Timeout
<rdar://problem/67331059>
Test expectation while investigated: https://trac.webkit.org/changeset/265818/webkit
*** This bug has been marked as a duplicate of bug 258641 ***