This new test (introduced in http://trac.webkit.org/changeset/78789) is failing now because it's entering the 'else' branch in the test for the GTK builds, causing the following error:
CONSOLE MESSAGE: line 41: ReferenceError: Can't find variable: fallbackElement
Anyway, even if we fixed that error (which looks a mistake in the test, see last comment on bug 50126) we'd be still getting the test failing in GTK as the test would keep entering the 'else' branch, and I can't know at the moment whether the fix for that would be immediate or not.
So currently skipping the test in GTK and leaving this bug open for keeping track of this issue.
This is no longer an issue since a long time ago (r79920). Resolving