OSS-fuzz long-ago discovered https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=45662 which we currently believe to be a bug in v8. I originally thought it was going to be fixed with https://bugs.chromium.org/p/v8/issues/detail?id=12722 but that no longer appears to be the case now that the `v8` crate has caught up and it still isn't fixed. Personally I've sort of lost an appetite for continuing to debug these issues so I figure it's best to just disable reference types with v8 for now and exercise the rest of the engine, e.g. simd.