[clang] [clang][CodeGen] Add reloadLinkModules to reload link modules for incremental compilation (PR #229741)

[Vassil Vassilev via cfe-commits]

vgvassilev wrote:

Thanks for the PR. Can you check if #229788 solves the same problem this one is solving with an existing client?

Also, I believe @aaronj0 from our team is doing adjacent work -- can we coordinate in discord?

https://github.com/llvm/llvm-project/pull/229741