OSV-2018-91 Heap-buffer-overflow in BEInt<unsigned int, 4>::operator unsigned int

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10881 Crash type: Heap-buffer-overflow READ 1 Crash state: BEInt::operator unsigned int OT::kern::hasdata hbotlayouthaskerning...