Add and use snmalloc, mimalloc for allocation performance

[WSLUser]

Description of the new feature/enhancement

Github randomly revealed a project from Microsoft that upon investigation seems like it would be pretty useful here to possibly boost performance for allocations. https://github.com/microsoft/snmalloc

Proposed technical implementation details (optional)

[WSLUser]

https://github.com/microsoft/mimalloc is more general purpose while snmalloc is for message-passing specifically. Use both as needed in places where allocations need to occur and can't simply be removed.