[clang] [AMDGPU] Make default AMDHSA Code Object Version to be 5 (PR #65410)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 approved this pull request.

I manually set the code object of the `libc` test suite to be `4` for the time being. That should unblock this.

https://github.com/llvm/llvm-project/pull/65410