swift234

IRGen: SIL ClosureInsts (almost).
Implement lowering of SIL ClosureInsts by packing the partial arguments into a heap allocation and emitting a thunk to unpack them and apply the closure function, similar to curried entry points. The test doesn't work quite yet because nested FuncDecls don't get visited anymore. I need to replace my hacked SIL path with a proper walk of the SIL module to generate functions and the AST to generate types.

Swift SVN r3817