[lld] [LLD][COFF] Swap the meaning of symtab and hybridSymtab in hybrid images (PR #135093)

[Martin Storsjö via llvm-commits]

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

LGTM overall, this sounds reasonable. This avoids the cases for `mainSymtab` which I always felt was a bit unintuitive.

https://github.com/llvm/llvm-project/pull/135093