[llvm] [SystemZ][z/OS] yaml2obj GOFF symbols (PR #75971)

[Yusra Syeda via llvm-commits]

ysyeda wrote:

> I'm not going to have time to review this until the new year, I'm afraid. Is it possible to split this into separate PRs, one for sections and one for symbols? If there's more than one variety of section, those could be separate PRs too.

@jh7370 I split this PR to just add the functionality for symbols. I'll create another PR for sections after this one is merged.

https://github.com/llvm/llvm-project/pull/75971