First step towards vftable generation with -cxx-abi microsoft PR13231

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173035 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes detection of class template specializations.

Now correctly formats:
template <> class A<int> {} a;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173038 91177308-0d34-0410-b5e6-96231b3b80d8