swift234

Now that we have the notion of an uncurry level, we can do a lot more 
detailed analysis of callees, which give us overload sets in more cases,
producing notes more consistently, and producing much better diagnostics
for the curried cases in test/Constraints/diagnostics.swift.

This also allows us to eliminate getCalleeName, which simplifies things
in CSDiags.


Swift SVN r30491