[llvm] [RemoveDIs][DebugInfo][IR] Add parsing for non-intrinsic debug values (PR #79818)

[Stephen Tozer via llvm-commits]

SLTozer wrote:

> It's also not a syntactic problem to report as parsing will succeed, but the Module will be ill formed, it's more akin to a Verifier error but it makes the most sense to detect it in the parser

SGTM, (this was the first way I implemented it anyway!)

https://github.com/llvm/llvm-project/pull/79818