[clang] [clang-tools-extra] [lldb] [clang] Reland: fix getTemplateInstantiationArgs (PR #201373)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

What changed were the two fixup commits on the PR on top of the original unchanged commit.

I don't think they would have caused this, but I'll run a reduction later.

https://github.com/llvm/llvm-project/pull/201373