[llvm] [Object] Provide operator< for ELFSymbolRef (PR #89861)

[James Henderson via llvm-commits]

jh7370 wrote:

> > Also, is there a reason you provide `<` but not `==`? I note that `DataRefImpl` has both.
> 
> DataRefImpl's `operator==` is good enough for comparison.

Why is DataRefImpl's `operator<` not good enough when the `operator==` is?

Also, please try to avoid force pushes in active reviews, per the LLVM guidelines. If rebasing is necessary, consider merging `main` into your branch instead.

https://github.com/llvm/llvm-project/pull/89861