swift234

Revert "Implement bridgeobject_retain/release merging in LLVMARCContract. rdar://22108790"

This reverts commit r32132.  It broke tests:

Swift :: 1_stdlib/FloatingPoint.swift.gyb
Swift :: 1_stdlib/NSStringAPI.swift
Swift :: 1_stdlib/Runtime.swift
Swift :: Interpreter/SDK/CoreGraphics_CGFloat.swift

Swift SVN r32142