swift234

SILGen: Project boxed payloads when switching indirect enums.

And fix some bugs in the switch implementation I ran into on the way:

- Make getManagedSubobject(CopyOnSuccess) really produce a CopyOnSuccess ConsumableManagedValue;
- Avoid invalidating address-only enums when they can't be unconditionally taken by copying the enum before projecting it. Ideally there'd be a copy_enum_data_addr instruction to do this more efficiently.

Swift SVN r29817