Remove uncurry level as a property of SILType/SILFunctionTypeInfo. During SIL type lowering, map a (Type, UncurryLevel) pair to a Swift CanType with the uncurried arguments as a Swift tuple. For example, T -> (U, V) -> W at uncurry level 1 becomes ((U, V), T) -> W--in reverse order to match the low-level calling convention. Update SILGen and IRGen all over the place for this representation change.
SILFunctionTypeInfo is still used in the SILType representation, but it's no longer load-bearing. Everything remaining in it can be derived from a Swift type.
This is an ABI break. Be sure to rebuild clean!
Swift SVN r5296
type, though; I had to define a WriteAsOperand function and
add a front() method to SILFunction to get this to work.
Rip out my dominators implementation and replace it with
LLVM's. I'd forgotten that LLVM's was actually generic.
Swift SVN r4717