[c++17] Visit class template explicit specializations just like all other...

[c++17] Visit class template explicit specializations just like all other class definitions in codegen.

If an explicit specialization has a static data member, it may be a definition and we may need to register it for emission.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@317296 91177308-0d34-0410-b5e6-96231b3b80d8