Refactor the diagnostic DeclContext printing.  No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216517 91177308-0d34-0410-b5e6-96231b3b80d8
PR20760: Don't assert (and produce better diagnostics) if a default initializer
contains an unmatched closing bracket token.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216518 91177308-0d34-0410-b5e6-96231b3b80d8