[clang] [clang][DebugInfo][test] Add tests for lambda capture packs (PR #160705)

[Michael Buch via cfe-commits]

Michael137 wrote:

> I think this test case is needed: (by-reference, with initializer, and is a pack)
> 
> ```c++
> return [&...params = args] {
>   return /* ... */;
> }();
> ```

The pack initialization isn't really important for debug-info (i don't think). The reason i have them in the tests is so we have multiple packs in the same capture lists. I do have a by-ref test for one of the packs

https://github.com/llvm/llvm-project/pull/160705