swift234

fix validation-test/stdlib/AssertDiagnostics.swift.  It is puking out a horrible type
signature from a diagnostic.  Instead of adjusting the diagnostic in the test, improve
the ASTPrinter to only print @noescape if @autoclosure isn't present.  The later implies
the first and is probably what the user wrote (note that at this level in the compiler
we don't have a real "isimplicit" bit).



Swift SVN r24216