he mentioned layout test is occasionally crashing in the GTK Debug bots.
See this log:
SVN rev 77917 / build #19084: Crashed
SVN rev 77916 / build #19083: Crashed
SVN rev 77915 / build #19082: Ok
SVN rev 77914 / build #19081: Ok
SVN rev 77912 / build #19080: Crashed
Changes in between 77912 and 77916 seem to be unrelated, hence skipping the test in GTK while not fixing the problem.
The crash, as dumped in the output:
ASSERTION FAILED: m_rootObject->isValid()
(../../Source/WebCore/bridge/jsc/BridgeJSC.cpp:109 void JSC::Bindings::Instance::willDestroyRuntimeObject(JSC::Bindings::RuntimeObject*))
Adding the author of the test to CC, perhaps he could help to find the root reason behind this.
*** This bug has been marked as a duplicate of bug 53716 ***