swift234

Reflection: Fixes for tuple types with labels, and varargs

Just drop labels when demangling TypeRefs. This is OK for now
since labels do not affect layout.

Vararg tuple types cannot appear directly as the type of
storage, however they can appear in function input types, and
therefore must be minimally supported. Since we don't plan on
doing function call reflection just yet, this doesn't matter
for now, but again we need to not crash.

With this patch, all TypeRefs in the Swift standard library now
successfully demangle and print.