Pull the Llama4 inference benchmark from lightning-thunder (#5578)

Pull the latest version of this script after substantial changes in the
lightning repo. The script is being "moved" into the fuser repo - it
will be deleted from lightning-thunder, and subsequent changes will be
merged into the fuser repo.

The script does not have any nvfuser changes at this moment. No configs
or model code are pulled inside yet.

Author: tbqh