OSV-2018-179 Heap-buffer-overflow in OT::post::accelerator_t::cmp_gids

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=11290 Crash type: Heap-buffer-overflow READ 5 Crash state: OT::post::acceleratort::cmpgids sortrcmpswap sortrsimple...