[lld] [LLD] Use uint64_t timestamp to overcome potential overflow (PR #81665)

[Fangrui Song via llvm-commits]

https://github.com/MaskRay requested changes to this pull request.

At least the ELF part change seems quite unnecessary to me. And if we really want to appease a static analyzer I'd do it another way.

https://github.com/llvm/llvm-project/pull/81665