Crate bench_sub_vm_recurse 

Recursive sub-VM spawn bench guest.

Endpoint 0 reads depth from φ[7] (a0). If zero, returns 0; otherwise derive_spawns a child Cap::Instance from the Image at SLOT_IMAGE_RECURSE (recursive — same image as the parent), threads depth - 1 to the child via φ[9] (host_call’s arg-passing convention), and CALLs the child at endpoint 0.