[clang] [clang][Driver] Use shared_ptr in the Compilation class (PR #116406)

[Fangrui Song via cfe-commits]

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

Using unique_ptr for `Args` is good, but I am not sure about shared_ptr for TranslatedArgs. There is no shared_ptr usage in clangDriver and we want to keep avoiding it.

https://github.com/llvm/llvm-project/pull/116406