support for MacOS Hypervisor.framework with multiple sandboxes

https://github.com/hyperlight-dev/hyperlight/pull/1674 added single sandbox suppot on macos. We should be able to support multiple sandboxes in parallel but there are some Hypervisor.framework api's that are missing/buggy. This is a place holder for that when it becomes ready.

There is also an approach for creating multiple sandboxes via remote processes that would do a similar thing but might have a higher overhead and that approach is covered in https://github.com/hyperlight-dev/hyperlight/issues/1706. Both can be supported simultaneously.

Start by reviewing PR #1674 for the existing single-sandbox macOS support, then compare its approach with issue #1706's remote-process alternative. Track the missing or buggy Hypervisor.framework APIs and determine when parallel sandboxes can be supported; done means multiple macOS sandboxes run concurrently.

Written by the indexing model from the issue text.