[lld] [ELF] Add internal InputFile (PR #78944)

[Peter Smith via llvm-commits]

https://github.com/smithp35 approved this pull request.

One small suggestion for a comment but otherwise LGTM.

There's a chance of future misuse by someone testing if a file == ctx.internalfile rather than call isInternal(). I think this could be mitigated by creating yet another FileType for linker script defined symbols but I don't think that it is worth it.

https://github.com/llvm/llvm-project/pull/78944