Support template template parameters

Summary:
We would fail to resolve (and thus display the value of) any
templated type which contained a template template argument even
though we don't really use template arguments.

This patch adds minimal support for template template arguments,
but I doubt we need any more than that.

Reviewers: clayborg, jingham

Subscribers: JDevlieghere, lldb-commits

Differential Revision: https://reviews.llvm.org/D44613

llvm-svn: 328984