[clang] [HIP][Clang][CodeGen] Handle hip bin symbols properly. (PR #107458)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

The current behavior of clang is expected.

when gpu binary is not specified, it is expected to be used for -fgpu-rdc and the __hip_gpubin_handle_ symbol needs to be external and unique since they may need to be merged for partial linking. Make them internal will break partial linking.

https://github.com/llvm/llvm-project/pull/107458