swift234

[ClangImporter] Don't look in protocols when seeing if a method is an accessor.

clang::ObjCMethodDecl::findPropertyDecl does a very general lookup to see if
a particular method /could/ be interpreted as a property accessor, but in
other places we were just using isPropertyAccessor() to decide whether a
method was /actually/ a property accessor. We should use the more conservative
of the two; I'm not sure if the former can /change/ if new protocols are
added (via categories).

This does cause one problem: the setter is now not available in any way on
the adopting class. We should still be exposing it as a method, even though
it's not available as a property.

Swift SVN r16035