live_restore_test_env.h (added in WT-13871) uses a connection wrapper to setup up the test environment for live restore unit testing. This is slow as it needs to create a full WiredTiger database, and it requires special logic on shutdown to handle the metadata/turtle files that were create but not needed for our testing.

This ticket is to investigate and implement using a mock_connection instead and calling __wt_live_restore_os directly rather than via the real connection's wiredtiger_open.

There's a few things to consider:

• We need to pass in the config as an array of strings. See the `config_parser` type and `setup_bm` for an example usage. Without this WiredTiger's config parsing will run into some nasty OOB memory
• The mock connection doesn't seem to support verbose logging at the moment. This is useful but not mandatory for this ticket