* [Distributed] NFC: Support encoding/decoding of substitutions by `FakeInvocation`
* [Distributed] Fix a bug in heterogeneous buffer iterator
`next()` did not advance offset by the size of the returned element
* [Distributed] NFC: Adjust `echo` test to handle two arguments
* [Distributed] Implement func metadata and executeDistributedTarget
dont expose new entrypoints
able to get all the way to calling _execute
* [Distributed] reimplement distributed get type info impls
* [Distributed] comment out distributed_actor_remoteCall for now
* [Distributed] disable test on linux for now
* [Distributed] towards DistributedActorSystem; synthesize the id earlier, since Identifiable.id
* Fix execute signature to what Pavel is working with
* funcs are ok in sil
* fixed lifetime of id in inits
* fix distributed_actor_deinit
* distributed_actor_local
* update more tests
fixing tests
fix TBD test
fix Serialization/distributed
fix irgen test
Fix null pointer crashes
* prevent issues with null func ptrs and fix Distributed prorotocol test
* fix deinit sil test
