[llvm] [ORC] Add AutoImportGenerator for COFF dllimport auto-import (PR #203914)

[Lang Hames via llvm-commits]

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

Looks good to me. Thanks very much for all your work on this @mkovacevic99, and for your patience with the review process!

https://github.com/llvm/llvm-project/pull/203914