[llvm] Fix compression header size check in ELF writer (PR #66888)

[David Blaikie via llvm-commits]

dwblaikie wrote:

> Merged as it is better than the wrong status quo..

> If someone wants to add a unittest for this case, it would be highly appreciated. But it's fair to say that the author and existing reviewers don't have bandwidth to do this :)

That's not generally how testing is handled in the LLVM project.

https://github.com/llvm/llvm-project/pull/66888