Implement [class.friend]p11's special name lookup rules for friend declarations
of local classes. We were previously handling this by performing qualified
lookup within a function declaration(!!); replace it with the proper scope
lookup.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188050 91177308-0d34-0410-b5e6-96231b3b80d8