Instantiation for member classes of class templates. Note that only

Instantiation for member classes of class templates. Note that only
the declarations of member classes are instantiated when the owning
class template is instantiated. The definitions of such member classes
are instantiated when a complete type is required.

This change also introduces the injected-class-name into a class
template specialization.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67707 91177308-0d34-0410-b5e6-96231b3b80d8