swift234

Remove FuncExpr.  Add CaptureInfo to FuncDecl.  Introduce AnyFunctionRef.

AnyFunctionRef is a universal function reference that can wrap all AST nodes
that represent functions and exposes a common interface to them.  Use it in two
places in SIL where CapturingExpr was used previously.

AnyFunctionRef allows further simplifications in other places, but these will
be done separately.


Swift SVN r8239