[clang] [llvm] [clang][DebugInfo] Emit DW_AT_object_pointer on function declarations with explicit `this` (PR #122928)

[Mats Jun Larsen via llvm-commits]

junlarsen wrote:

This causes a breaking change in the C-API which I believe can easily be avoided. I've submitted https://github.com/llvm/llvm-project/pull/124144 as a suggestion to keep compatability

https://github.com/llvm/llvm-project/pull/122928