swift234

SIL: Clean up SILType interface for functions.

Function and compound types have a bunch of extra calling convention and uncurrying info stuffed into a "SILTypeInfo" object that until now had to be fetched through the SILModule. Change the representation of SILType to be a PointerUnion of CanType and SILTypeInfo*, and move the uncurry level onto the SILTypeInfo for functions, so that SILTypeInfo is available directly through the SILType and SILType can go back to being pointer-sized.

Swift SVN r4582