Emit template type and value parameter DIEs for template variables.

Summary:
Ensure the TemplateParam attribute of the DIGlobalVariable node is translated into the proper DIEs.

Resolves https://bugs.llvm.org/show_bug.cgi?id=22119

Reviewers: dblaikie, probinson, aprantl, JDevlieghere, clayborg, whitequark, deadalnix

Reviewed By: dblaikie

Subscribers: llvm-commits

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D52057

llvm-svn: 343706