Keep track of the template parameter depth properly when we have

Keep track of the template parameter depth properly when we have
member templates declared inside other templates. This allows us to
match out-of-line definitions of member function templates within
class templates to the declarations within the class template. We
still can't handle out-of-line definitions for member class templates,
however.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@79955 91177308-0d34-0410-b5e6-96231b3b80d8