[lld] [lld][ELF] Resolve Symbols with same comdat index as Defined Symbols (PR #115140)

[Fangrui Song via llvm-commits]

MaskRay wrote:

Thanks for writing the initial patch, but I am going to take over #119332  Note, we could just drop keptComdat in this function. I am going to add more linkage tests as well.

https://github.com/llvm/llvm-project/pull/115140