swift234

Use objc_msgSendSuper[Stret] for foreign initializer delegation.

Introduce the SIL instruction peer_method, which references a method
in the given class or one of its superclasses (but not a subclass). It
IRGen's to objc_msgSendSuper[Stret] (vs. super_method IRGen'ing to
objc_msgSendSuper[Stret]2 for superclass lookup).

Use peer_method for initializer delegation to a foreign initializer
(i.e., an init-family method written in Objective-C) to close the
safety loophole introduced by initializer delegation in r11965. The
loophole still exists, but can only be triggered from Objective-C.

Teach definite initialization that peer_method really isn't a use of
self.



Swift SVN r11992