This module crashes node when running on a worker thread

[alcuadrado]

Hey,

We got a bug report in ethereumjs-util about it crashing node when requiring it in a worker thread.

I tried debugging it, but I don't know enough about node's C++ apis. It does seem to be related to this: https://stackoverflow.com/questions/62431517/fatal-error-in-v8handlescopecreatehandle-cannot-create-a-handle-without

You can reproduce it with this repository: https://github.com/APshenkin/ethereumjs-util-crash
Just install it and run node index.js. I was able to reproduce it in multiple versions of node, but sometimes it just doesn't crash. v12.18.2 does seem to crash deterministically though. Not sure if this changes anything, but I'm on macos.

I suspect that this issue may also be present in keccak, but couldn't produce it there.