[clang] [Clang][NFC] Remove TemplateArgumentList::OnStack (PR #79760)

[Krystian Stasiowski via cfe-commits]

sdkrystian wrote:

@erichkeane I added the following release note:
> Removed support for constructing on-stack `TemplateArgumentList`s. Interfaces should instead use `ArrayRef<TemplateArgument>` to pass template arguments.

I'm not entirely sure how to benchmark these changes. Perhaps I could determine the difference in AST memory usage compiling something like Boost or LLVM?

https://github.com/llvm/llvm-project/pull/79760