Implement TemplateArgument dumping in terms of Visitor

Summary: Split the output streaming from the traversal to other AST nodes.

Reviewers: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D55491

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@351012 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed