[clang-tools-extra] [clangd] Guard against null TemplateName in DumpVisitor (PR #181554)

[Aleksandr Platonov via cfe-commits]

https://github.com/ArcsinX requested changes to this pull request.

Thanks for the patch!

Can you please add a test for this fix? Test can be added here
clang-tools-extra/clangd/unittests/DumpASTTests.cpp (maybe you can minimize the code from the issue)

https://github.com/llvm/llvm-project/pull/181554