Relocatability of `deferred_codegen`

Currently `deferred_codegen` pushes a Job into a runtime dictionary. That runtime dictionary is only valid during the session.

I am wondering if instead we could use a de-virtualization strategy similar to Base.

```
@noinline function gpuc_deferred(f, args...)::Ptr end
@noinline function gpuc_lookup(mi, f, args)::Ptr end
```

Adding an abstract interpretation extension to refine `gpuc_deferred` -> `gpuc_lookup` looking up the corresponding `mi`.

After codegen (since we can't customize that yet) we scan the LLVM IR for `gpuc_lookup` and codegen the corresponding functions into the same module.

CUDA wants to get a function pointer and then wrap that in a `CuDeviceFunction` https://github.com/JuliaGPU/CUDA.jl/blob/e9928ca84509d7c686ea7ec413e1ad2d8176b987/src/compiler/execution.jl#L417

Start by tracing deferred_codegen and the proposed gpuc_deferred/gpuc_lookup path, including how the session-only runtime dictionary is used. Read CUDA's linked compiler/execution.jl call site and examine the proposed LLVM IR scan. Done means the generated module contains the corresponding functions without relying on the session dictionary and still produces the function pointer CUDA wraps in CuDeviceFunction.

Written by the indexing model from the issue text.