swift234

SILGen: Implement address-only type lowering.
Add a getLoweredType() method to SILGen's TypeInfo and logic to convert function signatures and address-only types to their SIL-level representations. Drive a (currently weak) type wedge between lowered and unlowered types by making a SILType subclass of CanType. Make SILConstants take on their lowered function types. This breaks a bunch of SIL test cases, which I've temporarily XFAILed until proper address-only type support can propagate through the rest of SILGen.

Swift SVN r3528