swift234

Use inherited initializers rather than cloning for Objective-C classes.

Make Objective-C initializers inherited according to the inheritance
rules we've specified. Prevent the Clang importer from manually
copying all of the initializers from every superclass into each
class. 

This eliminates a ton of extra allocating constructors generated when
importing Objective-C init methods. Now we only generate allocating
constructors for the init methods that are actually declared.

Note that initializer inheritance only actually works for
Objective-C-defined classes. More to come.



Swift SVN r14563