[lld] [ELF] Fix PROVIDE_HIDDEN -shared regression with bitcode file references (PR #112386)

[Peter Smith via llvm-commits]

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

LGTM. A map will definitely keep the return values in sync. Apologies for missing the corner case in first review.

https://github.com/llvm/llvm-project/pull/112386