55499 added a test that requires generating a double click event, which we are not yet able to generate in our DRT. FWIW, Qt added support to that in 55541.
DRT actually can generate double-click events in most cases (some leapForward uses might cause a failure). This failure seems related to: https://bugs.webkit.org/show_bug.cgi?id=30575
*** This bug has been marked as a duplicate of bug 30575 ***