Make these three types conform to the BridgedToObjectiveC
protocol, which is needed for array bridging. This is one part of
<rdar://problem/16533359>.
Because this must happen in the Foundation module, hack
swift_conformsToProtocol to look in the Foundation module for
conformances when it can't find them in the module corresponding to
the type. This is an egregious hack to an egregious hack, but it gets
us closer.
Swift SVN r15997
