[llvm] [C-API] Preserve backwards compatability for LLVMDIBuilderCreateObjectPointerType (PR #124144)

[Michael Buch via llvm-commits]

Michael137 wrote:

Oh and we'd have to adjust the OCaml bindings again...And that it's been sitting on top-of-tree, users of this have probably been updated. So changing this all back might be even more disruptive. So I'm not sure if we do want to land this after all actually

I should've just made the API always pass the `Implicit` flag, instead of adding that parameter. Then if someone needed it they could've updated the APIs.

https://github.com/llvm/llvm-project/pull/124144