swift234

[PrintAsObjC] Use _ObjectiveCBridgeable conformances to print bridged types.

Rather than hardcoding String/Array/Dictionary/Set to print as
NSString/NSArray/NSDictionary/NSSet, use _ObjectiveCBridgeable
conformances to determine how to print them. Another step toward
generalized _ObjectiveCBridgeable, although the general form is not
yet useful.