[Distributed] deinit aware of remote "properties" (lack thereof in storage)

[ktoso]

Class deinit, iff the class is a distributed actor must become aware that not all properties actually "really exist".

Only @_distributedActorIndependent properties are actually stored and may be released.
The other properties have never been initialized, and thus we must not destroy them.

A distributed deinit must:

• resignIdentity(self) we already do this earlier in SILGenDestructor, by calling emitDistributedActor_resignAddress(dd, selfValue, continueBB);
• it must check if it is remote, and if yes, it must NOT touch any properties in destruction since they are not "really there"
• if it is local, continue with the usual deinit

---

• I will refactor this more so it lives in SILGenDistributed and does not make the SILGenDestructor so ugly.
• clean up more of the warnings in SILGen

Review and hints how to better do this SIL very welcome! The good news is that non-distributed actors are of course not impacted by any change here.

[ktoso]

Note that today the memory actually exists for the actor, but it is zeroed out:

  HeapObject *alloc = swift_allocObject(classMetadata,
                                        classMetadata->getInstanceSize(),
                                        classMetadata->getInstanceAlignMask());

  // TODO: remove this memset eventually, today we only do this to not have
  //       to modify the destructor logic, as releasing zeroes is no-op
  memset(alloc + 1, 0, classMetadata->getInstanceSize() - sizeof(HeapObject));

we will remove that memset and any access to those "local only" properties would be reading/writing random memory, this is why this change in the destructor.

[ktoso]

@swift-ci please smoke test

[ktoso]

Heh silly failure because lack of [available 12.0] in SIL on linux

[ktoso]

@swift-ci please smoke test and merge

[ktoso]

@swift-ci please smoke test