Allow linkedDependencies on any IKG implementation #31461
Description
The API for batch compilation in kenerateKernel accept an option to link the platform.dill contents with the app. The option is called linkedDependencies. It is used today by dart2js to link the SDK into the app, for example.
The VM needs a similar capability for gen_snapshot (at least to be able to embed the vm_service library).
This is a blocking issue to be able to use IKG by default in the kernel-service isolate in the VM (Issue #31146).
/cc @aam