[llvm] [Object][Archive][NFC] Create all symbolic files objects before calculating offsets. (PR #85229)

[Daniel Paoliello via llvm-commits]

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

This is a really great cleanup IMHO, I found the `NextSymFile` thing very confusing when dealing with this code.

https://github.com/llvm/llvm-project/pull/85229