swift234

Revert "[stdlib] Remove workarounds for fixed bug"

This reverts commit r30148, since it regresses the following tests:

   Swift :: ClangModules/script.swift
   Swift :: Interpreter/currying_protocols.swift
   Swift :: Interpreter/if_expr.swift
   Swift :: Interpreter/protocol_extensions.swift
   Swift :: Interpreter/weak.swift
   Swift :: Interpreter/weak_objc.swift
   Swift :: PlaygroundTransform/array_did_set.swift
   Swift :: PlaygroundTransform/print.swift

Swift SVN r30159