swift234

SILGen: Partial codegen for property behaviors with DI initialization.

If a behavior has storage that can be initialized out-of-line, generate code in SILGen that uses stores to mark_uninitialized_behavior for eventual analysis by DI.

This is incomplete, particularly, it's missing code generation of glue thunks for accessors that require reabstraction, but I wanted to make sure the progress here didn't bitrot.