swift234

Switch the SIL parse to parse the file in a model similar to "immediate"
mode for normal .swift files.  We basically parse batches of non-sil function
decls, type check them as a batch, then process any SIL functions.  This allows
us to have mutually recursive types and other things that are fully sema'd and
that are referenced by SIL functions, without involving SIL functions too
intimately with type checking.

This does mean that SIL functions can't forward reference types, oh well.



Swift SVN r5243