[llvm] [clang] [mlir] [lld] [AMDGPU] Change default AMDHSA Code Object version to 5 (PR #73000)

[Saiyedul Islam via cfe-commits]

saiislam wrote:

> (patches like this should probably be broken up - test changes to the defaults in lld and llvm for instance don't depend on the change to the clang driver which is the only real semantic change in this patch, right? So probably only change the semantics of clang, and the tests that need to change there - then follow-up with separate commits that update other test coverage to be closer to the current defaults)

Thanks for the suggestion! Based on @dwblaikie and @JonChesterfield comments, I have broken this PR into 7 commits. Each commit deals with a specific subset (clang, lld, mlir, llvm manual tests, llvm autogenerated tests, etc.).
Hopefully this will simplify reviewers' job.

I will squash and merge these 7 commits into a single commit at the time of merging.

https://github.com/llvm/llvm-project/pull/73000