Include debug info for nested structs and classes

Include debug info for nested structs and classes

This includes nested types in the member list, even if there are no members of that type. Note that structs and classes have themselves as an "implicit struct" as the first member, so we skip implicit ones.

Differential Revision: http://reviews.llvm.org/D21705

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@274628 91177308-0d34-0410-b5e6-96231b3b80d8